Digestive Health: The Complete Guide

Key numbers at a glance

How your digestive system works

Your digestive tract is a long, muscular tube running from mouth to anus, with the liver, gallbladder and pancreas attached along the way. Its job is to break food down into molecules small enough to absorb, take in water and nutrients, and get rid of what is left. Chewing and saliva start the process. The esophagus moves food to the stomach, where acid and enzymes break down protein and the food is churned into a liquid. A ring of muscle at the bottom of the esophagus normally stops that acid from flowing back up.

Most absorption happens in the small intestine, helped by bile from the liver and gallbladder, which breaks up fat, and enzymes from the pancreas. What reaches the large intestine, or colon, is mostly water, fiber and other material the body cannot digest. The colon absorbs water and salts, and its trillions of bacteria ferment fiber, producing gas and compounds that nourish the gut lining. The rectum stores stool until it is convenient to pass it.

All of this is coordinated by waves of muscle contraction and by an extensive network of nerves in the gut wall that communicates constantly with the brain. That gut-brain connection explains why stress can cause diarrhea or stomach pain, why some people feel nauseous before a big event, and why treatments aimed at the brain, such as certain therapies, can help gut symptoms. It also explains why the gut is so sensitive to routine, sleep, medicines and what and when you eat.

What is normal and what is not

There is no single normal for bowel habits. Some people go once or more a day and others every couple of days, and both can be healthy. What matters most is what is normal for you, and whether that has changed. Stools that are soft, formed and easy to pass without straining are the goal. Constipation is generally described as fewer than three bowel movements a week, or stools that are hard, dry, painful or difficult to pass.

Gas is normal too. Everyone passes gas many times a day, mostly from bacteria fermenting fiber and from swallowed air. More beans, vegetables and whole grains usually mean more gas, especially when you first increase them, and that is a sign the bacteria in your colon are being fed, not that something is wrong. Stool color varies with food and medicines; iron tablets and bismuth can turn it dark or black.

Some changes are not normal and should not be explained away. A persistent change in your bowel habits lasting more than a few weeks, blood in or on your stool, black or tarry stools without an obvious cause, unexplained weight loss, ongoing abdominal pain, difficulty swallowing and waking at night to have diarrhea all need a doctor's assessment. These symptoms usually turn out to have a benign cause, but some of them can be early signs of inflammatory bowel disease, ulcers or colorectal cancer, which are much easier to treat when found early.

The foundations: fiber, fluids and routine

Fiber is the part of plant foods that you cannot digest. It comes in two broad kinds. Soluble fiber, found in oats, beans, lentils, apples and psyllium, absorbs water and forms a gel that softens stool and slows digestion. Insoluble fiber, found in wheat bran, whole grains and the skins of vegetables, adds bulk and speeds things along. Fiber also feeds the bacteria in your colon. The Dietary Guidelines for Americans recommend 14 grams of fiber for every 1,000 calories, which works out at roughly 22 to 34 grams a day for adults, depending on age and sex. Most Americans eat far less.

Increase fiber gradually over a few weeks rather than overnight, and drink more fluid as you do. A sudden jump in fiber is a common cause of bloating and cramps, and fiber without enough fluid can make constipation worse rather than better. Water is the best default, though all drinks and the water in food count toward your fluid intake.

Routine matters more than most people expect. The gut is most active after waking and after meals, so regular mealtimes and allowing unhurried time in the bathroom after breakfast help. Ignoring the urge to go lets stool sit longer in the colon, where more water is absorbed and it becomes harder. Physical activity stimulates the gut, and even a daily walk helps. Sitting with your knees raised above your hips, using a small footstool, straightens the passage out of the rectum and makes emptying easier.

• Swap refined grains for whole grains: oatmeal, whole-wheat bread, brown rice
• Add a serving of beans, lentils or chickpeas to meals several times a week
• Eat whole fruit and vegetables, with skins where practical, rather than juice
• Limit heavily processed foods, which tend to be low in fiber and high in fat and sodium

Constipation and hemorrhoids

Constipation is one of the most common digestive complaints in the US. Usual causes are low fiber, too little fluid, inactivity, ignoring the urge to go, travel and changes in routine. Medicines are a frequently overlooked cause: opioid painkillers, iron supplements, some antidepressants, some antacids and some blood pressure medicines can all slow the bowel. If constipation started when you began a new medicine, ask your pharmacist or doctor whether it could be responsible.

Most constipation responds to fiber, fluid, activity and routine. If those are not enough, over-the-counter laxatives can help. A bulk-forming laxative such as psyllium is often tried first; it works like dietary fiber and must be taken with plenty of water. If stools remain hard, an osmotic laxative such as polyethylene glycol draws water into the bowel. Stimulant laxatives are useful occasionally but should not be used long term without medical advice. Children, pregnant women and people with other health conditions should check with a doctor or pharmacist before using laxatives.

Hemorrhoids are swollen blood vessels in and around the anus. They are very common, and straining and constipation are the main contributors. Typical symptoms are bright red blood on the toilet paper, itching, discomfort and sometimes a soft lump. Treating constipation is the most effective step. Avoid straining and long sessions on the toilet, including scrolling on your phone. Warm sitz baths and over-the-counter creams can ease symptoms in the short term, but steroid creams should not be used for long periods without advice.

The danger with hemorrhoids is assuming that any rectal bleeding comes from them. Bleeding that is dark, mixed in with stool, persistent, or accompanied by a change in bowel habits, weight loss or abdominal pain needs to be checked, because colorectal cancer and inflammatory bowel disease can cause similar bleeding. A doctor can usually examine the area in a few minutes, and may suggest a colonoscopy depending on your age, symptoms and family history. A hard, very painful lump near the anus can be a clotted hemorrhoid and is worth being seen promptly.

Diarrhea and stomach bugs

Diarrhea means passing loose or watery stools more often than is normal for you. Acute diarrhea, lasting a day or two, is usually caused by a viral infection such as norovirus, by contaminated food or water, or by medicines including antibiotics. Diarrhea lasting two to four weeks is described as persistent, and diarrhea lasting four weeks or more is chronic and needs investigation, since it can be caused by conditions such as celiac disease, inflammatory bowel disease, microscopic colitis or medicine side effects.

In otherwise healthy adults the main risk of short-term diarrhea is dehydration rather than the infection itself. Keep drinking, and use an oral rehydration solution if you are losing a lot of fluid. These solutions contain salts and sugar in proportions that help the gut absorb water, and they are especially useful for children and older adults, who dehydrate faster. There is no need to stop eating; eat when you feel able, starting with plain foods.

Over-the-counter antidiarrheal medicines such as loperamide (Imodium) can reduce the number of trips to the bathroom, but avoid them if you have a fever or blood in your stool, which can signal an infection the body needs to clear. Bismuth subsalicylate contains a salicylate related to aspirin and should not be given to children or teenagers. Do not give antidiarrheal medicines to young children unless a doctor advises it.

Stopping the spread

Norovirus spreads extremely easily, through contaminated hands, surfaces, food and the air around vomiting. Wash your hands with soap and water, since alcohol-based hand sanitizer works poorly against norovirus. Do not prepare food for other people while you are sick and for at least 2 days after symptoms stop, and stay home from work or school for 48 hours after the last episode of vomiting or diarrhea. Clean contaminated surfaces with a bleach-based cleaner, following the product label, and wash soiled laundry on a hot cycle.

Heartburn, reflux and indigestion

Acid reflux happens when stomach contents flow back up into the esophagus. The main symptom is heartburn, a burning feeling behind the breastbone, often with an acid or bitter taste and regurgitation. It is typically worse after large meals, when lying flat or bending over, and at night. Occasional reflux is common and normal. Reflux that is frequent, troublesome or causes complications is called gastroesophageal reflux disease (GERD), and over time it can inflame the esophagus.

Common triggers are large meals, eating late, alcohol, smoking and excess weight, which increases pressure on the stomach. Some people also notice that fatty or spicy foods, chocolate, coffee or peppermint make symptoms worse, though triggers vary and there is no need to cut out foods that do not bother you. Eating smaller meals and leaving about three hours between eating and lying down help many people. For night-time symptoms, raising the head of the bed by putting blocks under the legs or using a wedge works; extra pillows do not, because they bend you at the waist.

Antacids give quick, short-lived relief. H2 blockers and proton pump inhibitors (PPIs) reduce acid production and are available over the counter and by prescription. Over-the-counter PPIs are intended for a defined course, not continuous use without advice. If you have been taking a PPI for months, ask your doctor to review whether you still need it and at what dose; some people do need long-term treatment, but many can step down.

Indigestion, or dyspepsia, describes discomfort or fullness in the upper abdomen, sometimes with nausea. It overlaps with reflux. Peptic ulcers, open sores in the lining of the stomach or the first part of the small intestine, can cause similar pain and are mostly caused by infection with Helicobacter pylori bacteria or by regular use of NSAID painkillers such as ibuprofen, naproxen and aspirin. If you have persistent indigestion, especially if you take NSAIDs, your doctor may test for H. pylori, which can be treated with antibiotics.

When chest pain is not heartburn

Heart pain can feel very like heartburn, and the two are easy to confuse, particularly in women, older adults and people with diabetes. Call 911 for chest pain, pressure or tightness lasting more than a few minutes, or pain spreading to the arm, neck, jaw or back, especially with shortness of breath, sweating, nausea or lightheadedness. Do not assume it is reflux because you have had heartburn before.

Irritable bowel syndrome and bloating

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction. The gut looks normal on tests, but the way the gut and brain communicate is altered, so the bowel is more sensitive and its movements less regular. The core feature is recurrent abdominal pain related to bowel movements, together with a change in how often you go or what your stools look like. Some people mainly have constipation, some mainly diarrhea, and some alternate. Bloating is very common. IBS is diagnosed positively from the pattern of symptoms, with a limited number of tests, including a blood test for celiac disease, rather than by exhaustively ruling out everything else.

IBS is not dangerous and does not lead to cancer, but it can be genuinely disabling, and it deserves to be taken seriously. First-line steps are regular meals, adequate fluids, limiting caffeine, alcohol and fizzy drinks, and adjusting fiber: soluble fiber such as psyllium often helps, while insoluble bran often makes symptoms worse. Keeping a symptom and food diary for a few weeks before changing anything makes patterns much easier to see.

If first-line measures are not enough, a low FODMAP diet can help many people. FODMAPs are types of carbohydrate that are poorly absorbed and fermented by gut bacteria. The diet is done in phases, cutting FODMAPs for a few weeks and then reintroducing them one group at a time to find your personal triggers. It is complicated and restrictive, so it is best done with a registered dietitian and is not meant to be followed strictly long term. Psychological treatments, including cognitive behavioral therapy and gut-directed hypnotherapy, have good evidence in IBS, and medicines can target pain, diarrhea or constipation.

When bloating needs a closer look

Most bloating is related to diet, constipation, IBS or swallowed air, and eating more slowly, cutting back on carbonated drinks and gum, and treating constipation often help. But new bloating that happens almost every day and does not go away, particularly with feeling full quickly, pelvic or abdominal pain or needing to urinate more often, can be a sign of ovarian cancer and should be checked promptly. Bloating with weight loss, rectal bleeding or a change in bowel habits also needs assessment.

Celiac disease, food intolerance and food allergy

These three are often confused, but they work differently and carry very different levels of risk. Celiac disease is an autoimmune condition. Food allergy is an immune reaction that can be life-threatening. Food intolerance does not involve the immune system and, while unpleasant, is not dangerous in the same way. Getting the right label matters because the management is different for each.

Celiac disease

In celiac disease, eating gluten, a protein in wheat, barley and rye, triggers an immune reaction that damages the lining of the small intestine and impairs absorption. Symptoms vary widely: diarrhea, bloating, weight loss, fatigue, mouth ulcers, iron-deficiency anemia, an itchy blistering rash, or sometimes very few symptoms at all. It is substantially underdiagnosed. Testing starts with blood tests and is usually confirmed with an upper endoscopy and biopsy.

The crucial point is to keep eating gluten until testing is complete, because removing it first can make results look falsely normal. Once diagnosed, treatment is a strict, lifelong gluten-free diet, ideally planned with a registered dietitian. In the US, foods labeled gluten-free must contain less than 20 parts per million of gluten under FDA rules. Oats are often cross-contaminated unless labeled gluten-free. Parents, siblings and children of people with celiac disease are at higher risk and should ask about testing.

Food intolerance

Food intolerance is a reproducible reaction to a food that does not involve the immune system. Lactose intolerance, where the body makes too little of the enzyme that digests milk sugar, is the most common example, causing gas, bloating and diarrhea after dairy. Symptoms are usually dose-related, so many people with lactose intolerance can manage small amounts, hard cheeses or yogurt. The reliable way to identify an intolerance is careful elimination and reintroduction, ideally with a dietitian. Commercial IgG blood tests and hair analysis for food intolerance do not diagnose it and can lead to unnecessary restriction.

Food allergy

Food allergy involves the immune system and can cause hives, swelling, vomiting and, in its most severe form, anaphylaxis, which can be fatal. Reactions usually start within minutes to a couple of hours of eating the food. Swelling of the lips, tongue or throat, difficulty breathing or swallowing, widespread hives with faintness, or collapse after eating need an epinephrine auto-injector if one is available and a call to 911. Suspected food allergy should be assessed by a doctor or allergist rather than managed by trial and error.

Colorectal cancer: screening and warning signs

Colorectal cancer usually develops slowly from polyps, small growths in the lining of the colon or rectum, over many years. Screening can find cancer early, when it is highly treatable, and can also prevent it by finding and removing polyps before they become cancerous. Rates in adults under 50 have been rising, which is one reason the starting age was lowered. The USPSTF recommends screening for adults aged 45 to 75, and an individual decision with your doctor from 76 to 85.

You have a choice of tests, and the best test is the one you will actually complete. Home stool tests are done privately and mailed back; any abnormal stool test must be followed by a colonoscopy, or the screening is incomplete. Colonoscopy examines the whole colon with a camera, removes polyps during the same procedure, and needs bowel preparation the day before and a ride home afterward. Under the Affordable Care Act, most private plans cover screening without a copay, and the follow-up colonoscopy after an abnormal stool test is also generally covered as part of screening; check with your plan.

If you have a parent, sibling or child who had colorectal cancer or advanced polyps, especially at a young age, or if you have inflammatory bowel disease or certain inherited conditions, you may need to start earlier and be screened more often. Tell your doctor about your family history well before 45. Find out the age at which your relative was diagnosed if you can, because that affects when you should begin, and share your own results with siblings and children since their risk may change too.

• Fecal immunochemical test (FIT): a home stool test every year
• Stool DNA-FIT test: every 1 to 3 years
• CT colonography: every 5 years
• Flexible sigmoidoscopy: every 5 years, or every 10 years with a yearly FIT
• Colonoscopy: every 10 years if results are normal

Symptoms are not for screening

Screening is for people without symptoms. If you have rectal bleeding, blood in your stool, a change in bowel habits lasting more than a few weeks, unexplained weight loss, ongoing abdominal pain or iron-deficiency anemia, see your doctor for a diagnostic evaluation regardless of your age or when you were last screened. Do not wait for your next routine test, and do not let a normal result last year reassure you about a new symptom this year.

Other conditions worth knowing about

Inflammatory bowel disease (IBD), mainly Crohn's disease and ulcerative colitis, is different from IBS. In IBD the immune system causes ongoing inflammation that damages the gut, and it shows up on tests. Symptoms include persistent diarrhea, often with blood or mucus, abdominal pain, urgency, weight loss and fatigue, sometimes with joint, skin or eye problems. It often starts in young adults. IBD is a long-term condition managed by a gastroenterologist, and modern medicines can control it well for many people.

Gallstones are hardened deposits in the gallbladder. Many cause no symptoms, but a stone that blocks a duct causes intense pain in the upper right or middle abdomen, often after a fatty meal, lasting from under an hour to several hours. Pain with fever, yellowing of the skin or eyes, or dark urine suggests infection or blockage and needs urgent care. Diverticular disease involves small pouches in the wall of the colon, which are common with age; when they become inflamed, usually causing pain low on the left side with fever, it is called diverticulitis and needs medical assessment.

The liver is part of the digestive system too. Its most common problems in the US are linked to alcohol, excess weight and diabetes, and viral hepatitis. Liver disease is usually silent until it is advanced. If you drink, the Dietary Guidelines for Americans advise up to two drinks a day for men and one for women, where a standard drink is 14 grams of alcohol. Ask your doctor about hepatitis C testing, which guidelines recommend at least once in adulthood, and about hepatitis A and B vaccines.

Probiotics, supplements and gut health claims

The bacteria living in your gut, collectively called the gut microbiome, are a fast-moving area of research, and marketing has run well ahead of the evidence. Probiotics are live bacteria or yeasts taken for a health benefit. Their effects are specific to the strain and the condition, so a product that helps one problem tells you nothing about another, and products are not interchangeable. The strongest evidence is for preventing antibiotic-associated diarrhea with some specific strains. In the US, most probiotics are sold as dietary supplements, which do not need FDA approval before sale.

If you want to try one, choose a product that names the genus, species and strain, and that has been studied for your particular problem; your pharmacist can help. Stop if your symptoms worsen. People with a weakened immune system, a central line, or a serious illness, and premature babies, should not take live probiotic products without medical advice, because rare serious infections have been reported. For most people, eating a variety of fiber-rich plant foods does more for gut bacteria than any capsule.

Be wary of colon cleanses, detox teas and products promising to "reset" your gut. The colon does not need cleansing, and some of these products contain stimulant laxatives or other ingredients that can cause dehydration, electrolyte problems or interactions with medicines. Herbal products marketed for digestion or the liver are also not automatically safe. Tell your doctor or pharmacist about any supplement you take.

Specific groups, your doctor and a four-week plan

Some groups need extra care. Babies, young children and older adults dehydrate quickly with diarrhea and vomiting, so get advice early. Pregnancy commonly causes heartburn and constipation; check with your doctor or pharmacist before using any medicine, including laxatives and antacids. Older adults are more likely to be on medicines that affect the gut, and new symptoms after 50 deserve a lower threshold for investigation. People with diabetes can develop slowed stomach emptying, and anyone taking regular NSAIDs has a higher risk of ulcers and bleeding.

When you see your doctor, describe your symptoms specifically: how long they have lasted, how often you go, what your stools look like, whether there is blood, what makes things better or worse, and any weight change. Bring your medicine and supplement list and any food diary. Mention family history of celiac disease, IBD, colorectal or ovarian cancer. If you are working on a long-standing problem such as constipation, reflux or IBS, the four weeks below are a realistic place to start.

• Week 1: keep a food, symptom and bowel diary without changing anything, and review your medicines with a pharmacist
• Week 2: set regular mealtimes, leave three hours between your last meal and bed, and add one serving of fiber a day with an extra glass of water
• Week 3: add a daily walk, keep building fiber gradually, and cut back on alcohol, carbonated drinks and late heavy meals
• Week 4: review the diary for patterns, book a visit if symptoms persist or any red flag appears, and check whether you are due for colorectal cancer screening

Every guide in this topic

• Irritable Bowel Syndrome: What Published Guidance Supports
• What the Guidance Really Says About Constipation
• What the Guidance Really Says About Acid Reflux
• Celiac Disease: What Published Guidance Supports
• Bloating: Sorting the Evidence From the Noise
• What the Guidance Really Says About Diarrhea
• What the Guidance Really Says About Hemorrhoids
• Food Intolerance: What the Evidence Actually Says
• What the Guidance Really Says About Probiotics
• The Evidence on Liver Health, Without the Hype

Frequently asked questions

How often should I have a bowel movement?

There is no single normal. Healthy patterns range from more than once a day to every couple of days. What matters is what is usual for you and whether stools are soft and easy to pass. Constipation is generally described as fewer than three bowel movements a week or hard, difficult stools. A lasting change from your usual pattern, especially with blood or weight loss, is worth discussing with your doctor.

What is the best way to increase fiber?

Increase it gradually over a few weeks, adding one extra serving at a time, and drink more fluid as you go. Good sources include oats, beans and lentils, whole grains, fruit and vegetables with their skins. The US recommendation is 14 grams per 1,000 calories, about 22 to 34 grams a day for adults. Adding a lot at once commonly causes gas, bloating and cramps.

When is diarrhea serious?

See your doctor for diarrhea lasting more than 2 days in an adult or more than 24 hours in a child, blood or pus in the stool, black stools, severe abdominal pain, a high fever, or signs of dehydration such as dizziness on standing and passing very little urine. Get advice early for babies, older adults, pregnant women and people with weakened immune systems. Call 911 for confusion or fainting.

Is it safe to take heartburn medicine every day?

Over-the-counter proton pump inhibitors are designed for a defined course, not indefinite use without advice. If you need them regularly or symptoms keep returning, see your doctor, who can check for underlying causes and decide whether you need longer-term treatment and at what dose. Some people do need ongoing treatment, but many can reduce or stop. See your doctor promptly for difficulty swallowing, weight loss or vomiting.

How do I know if I have IBS or something more serious?

IBS causes recurring abdominal pain linked to bowel movements, with changes in stool frequency or form, and it does not cause bleeding, weight loss or anemia. Your doctor will usually test for celiac disease and look for warning signs before diagnosing IBS. Rectal bleeding, unexplained weight loss, waking at night with diarrhea, a family history of bowel or ovarian cancer, or new symptoms after 50 need further investigation.

Should I try a gluten-free diet to see if it helps?

Not before getting tested for celiac disease. Removing gluten first can make blood tests and biopsies look falsely normal, which can leave you without a clear diagnosis. Keep eating gluten regularly until testing is complete. If celiac disease is ruled out and you still suspect gluten or wheat bothers you, a dietitian can help you test that properly without unnecessarily restricting your diet.

Do probiotics work?

Some do, for some conditions. Effects depend on the specific strain, so products are not interchangeable. The strongest evidence is for preventing antibiotic-associated diarrhea with certain strains. Choose a product that lists the genus, species and strain and has been studied for your problem. People with weakened immune systems or serious illness should check with their doctor first, and fiber-rich foods remain the better-supported way to support gut bacteria.

When should I start colorectal cancer screening?

Guidelines recommend screening from age 45 to 75 for people at average risk, with options including a yearly home FIT stool test, a stool DNA-FIT test every 1 to 3 years, or colonoscopy every 10 years. From 76 to 85 it is an individual decision. If a close relative had colorectal cancer or advanced polyps, or you have inflammatory bowel disease, talk to your doctor about starting earlier.

Is rectal bleeding always hemorrhoids?

No. Hemorrhoids are a common cause of bright red blood on the toilet paper, but other conditions, including colorectal cancer and inflammatory bowel disease, can cause bleeding too. See your doctor about any rectal bleeding, especially if it is dark, mixed with stool, persistent, or comes with a change in bowel habits, weight loss or abdominal pain. Call 911 for heavy bleeding with dizziness or fainting.

Are colon cleanses or detox teas good for digestion?

No. The colon clears itself and does not need cleansing. Colon cleanses and detox products have no good evidence of benefit, and some contain stimulant laxatives or other ingredients that can cause cramping, dehydration, electrolyte problems or interactions with medicines. A steady intake of fiber, fluids and regular activity does far more for bowel health. Check with your doctor or pharmacist before trying any digestive supplement.

When to speak to a doctor

See your doctor for a change in bowel habits lasting more than a few weeks, blood in or on your stool, unexplained weight loss, persistent abdominal pain or bloating, difficulty or pain swallowing, food sticking, persistent vomiting, waking at night with diarrhea, iron-deficiency anemia, or new digestive symptoms after age 50. Get advice early about diarrhea in babies, older adults, pregnant women and people with weakened immune systems. Go to the emergency room or call 911 for vomiting blood or material that looks like coffee grounds, black tarry stools, heavy rectal bleeding with dizziness or fainting, sudden severe abdominal pain, a swollen rigid abdomen with vomiting and no gas or stool passing, or abdominal pain with yellowing of the skin and fever. Call 911 for chest pain that could be the heart, or for swelling of the lips or throat or difficulty breathing after eating. Call Poison Control at 1-800-222-1222 if someone has swallowed too much of a medicine or a harmful substance.

Where this comes from

• National Institute of Diabetes and Digestive and Kidney Diseases — Irritable Bowel Syndrome (IBS)
• National Institute of Diabetes and Digestive and Kidney Diseases — Constipation
• National Institute of Diabetes and Digestive and Kidney Diseases — Diarrhea
• National Institute of Diabetes and Digestive and Kidney Diseases — Acid Reflux (GER & GERD) in Adults
• National Institute of Diabetes and Digestive and Kidney Diseases — Celiac Disease
• US Preventive Services Task Force — Colorectal Cancer: Screening
• CDC — Preventing Norovirus
• FDA — Gluten-Free Means What It Says
• NIH Office of Dietary Supplements — Probiotics: Fact Sheet for Consumers
• Dietary Guidelines for Americans — Dietary Guidelines for Americans, 2020-2025

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.