Stomach Problems: The Complete Guide
What counts as a stomach problem
Stomach problems are symptoms such as upper belly pain, burning, nausea, bloating, early fullness, belching and heartburn that start in or near the stomach. Most are short-lived and linked to food, medicines, infections or stress. Some, such as ulcers, reflux disease and gastroparesis, are ongoing conditions that need a doctor’s diagnosis and treatment.
People often say “stomach” when they mean the whole belly, so this guide also covers common problems lower down, such as gas, constipation and irritable bowel syndrome (IBS). Digestive problems are very common: the NIDDK estimates that 60 to 70 million people in the United States are affected by digestive diseases (NIDDK).
Indigestion alone affects up to 20% of people in the United States each year, and about 7 in 10 people who see a doctor for it are diagnosed with functional dyspepsia, meaning no disease is found to explain the symptoms (NIDDK). In other words, most stomach trouble is real and uncomfortable but not dangerous. The skill is knowing which symptoms fit that pattern and which do not.
How your stomach works, and where things go wrong
The stomach is a muscular bag between the esophagus (food pipe) and the small intestine. When food reaches the bottom of the esophagus, a ring of muscle called the lower esophageal sphincter relaxes to let it in, then closes to keep stomach contents from flowing back up. Glands in the stomach lining make acid and enzymes, the stomach muscles mix food with these juices, and the stomach slowly empties the mixture into the small intestine (NIDDK).
Nerves and hormones run the whole process. The gut has its own network of nerves in its walls, and signals travel back and forth between the gut and the brain. These signals control how fast food moves, when digestive juices are released, and when you feel hungry or full (NIDDK).
Most stomach problems come from a breakdown in one of these steps:
- The valve leaks. If the lower esophageal sphincter is weak or relaxes at the wrong time, acid moves up and causes heartburn or reflux.
- The lining is damaged. Infection with H. pylori bacteria, pain relievers such as ibuprofen, or alcohol can irritate the lining, leading to gastritis or ulcers.
- The muscles move too slowly. When the stomach empties slowly, as in gastroparesis, food sits too long and causes fullness, nausea and vomiting.
- The nerves are too sensitive. In functional dyspepsia and IBS, the gut looks normal but is more sensitive to its own normal activity, so ordinary digestion can hurt.
- Germs get in. Viruses, bacteria and parasites from food or water can cause a short burst of vomiting, cramps and diarrhea.
- Food is not fully digested. Carbohydrates the small intestine cannot absorb pass to the large intestine, where bacteria ferment them and make gas.
Common stomach problems and what they feel like
This table summarizes the most common problems. The sections below explain each one in plain terms.
| Problem | Typical symptoms | Common causes |
|---|---|---|
| Indigestion (dyspepsia) | Upper belly pain or burning, early fullness, bloating, nausea, belching | Often unknown (functional dyspepsia); ulcers, infections, some medicines |
| Acid reflux and GERD | Heartburn, sour taste, regurgitation, chronic cough | Weak or relaxed valve, excess weight, pregnancy, smoking, some medicines |
| Gas and bloating | Belching, a swollen or tight belly, passing gas | Swallowed air, fermentation of some carbohydrates |
| Gastritis | Often none; sometimes upper belly pain, nausea, poor appetite | H. pylori, NSAIDs, alcohol, bile reflux |
| Peptic ulcers | Dull or burning upper belly pain, often between meals or at night | H. pylori and NSAIDs |
| Gastroparesis | Fullness long after meals, nausea, vomiting | Diabetes, surgery, some medicines; often unknown |
| IBS | Repeated belly pain with diarrhea, constipation or both | Gut-brain interaction problems |
| Food poisoning | Vomiting, diarrhea, cramps, fever | Bacteria, viruses, parasites, toxins |
| Lactose intolerance | Gas, bloating, diarrhea after dairy | Low levels of the enzyme lactase |
Indigestion and functional dyspepsia
Indigestion is a group of symptoms rather than a disease: pain, burning or discomfort in the upper belly, feeling full too soon, bloating, nausea or belching. When it keeps coming back and no cause is found, doctors call it functional dyspepsia, a disorder of how the gut and brain work together. Possible contributors include certain foods, oversensitivity to stomach acid, a stomach that does not relax well to hold food, anxiety and depression (NIDDK).
Some medicines can cause indigestion, including certain antibiotics, NSAIDs, iron supplements, some bone medicines, steroids and GLP-1 drugs used for diabetes and weight loss (NIDDK). If symptoms began after starting a new medicine, ask your doctor or pharmacist. Do not stop a prescribed drug on your own.
Acid reflux and GERD
Almost everyone has reflux now and then. When it causes repeated, bothersome symptoms or damage, it is called gastroesophageal reflux disease (GERD), which affects about 20% of people in the United States (NIDDK). Typical symptoms are heartburn, a burning feeling behind the breastbone, and regurgitation, a sour taste of food or acid in the throat. Some people have chest pain, nausea, trouble swallowing or a chronic cough instead (NIDDK).
Untreated GERD can inflame the esophagus and, over time, narrow it or change its lining (Barrett’s esophagus), which is why long-lasting heartburn deserves a doctor visit (NIDDK).
Gas, belching and bloating
Some gas is normal. People belch up to 30 times a day and pass gas 8 to 14 times a day on average, and up to 25 times is still considered normal (NIDDK). Gas comes from swallowed air and from bacteria in the large intestine breaking down carbohydrates the small intestine did not digest. Beans, lentils, broccoli, cauliflower, high-fiber foods, fructose, lactose and sugar alcohols such as sorbitol are common culprits (NIDDK).
If gas is your main complaint, our guide on what to eat when your stomach hurts from gas lists gentler options, and foods that are hard to digest explains why certain foods cause more trouble.
Gastritis and peptic ulcers
Gastritis is inflammation of the stomach lining. Most people with it have no symptoms, but some get upper belly pain, nausea, early fullness or poor appetite. The most common causes are H. pylori infection and long-term contact with irritants such as NSAIDs, alcohol and bile (NIDDK).
A peptic ulcer is an open sore in the lining of the stomach or the first part of the small intestine. About 1% to 6% of people in the United States have one (NIDDK). The pain is often dull or burning and may come when the stomach is empty or at night. The two most common causes are H. pylori and NSAIDs such as aspirin, ibuprofen and naproxen, especially at high doses or over long periods (NIDDK).
Gastroparesis
In gastroparesis, the stomach empties too slowly even though nothing is blocking it. Symptoms include feeling full soon after starting a meal or long after finishing, nausea, vomiting, bloating and upper belly pain. Diabetes is the most common known cause, because it can damage the nerves that control the stomach muscles, but in most cases no cause is found (NIDDK). Some pain medicines and antidepressants can slow emptying and cause similar symptoms.
IBS and other lower-belly problems
Irritable bowel syndrome is repeated belly pain along with diarrhea, constipation or both, without visible damage in the gut. About 12% of people in the United States have it, and women are up to twice as likely as men to develop it (NIDDK). Constipation, diarrhea and lactose intolerance also cause cramps and bloating that people often describe as stomach problems. See our guides to constipation relief and what to eat when your stomach is upset with diarrhea.
Some conditions show up as stomach pain even though they start elsewhere. Gallstones can cause attacks of pain in the upper right belly lasting several hours, often after a heavy meal and in the evening (NIDDK). Small intestinal bacterial overgrowth (SIBO) can cause bloating and diarrhea, and researchers are still sorting out its other possible signs, as we cover in Does SIBO Cause Bad Breath?
Stomach bugs and food poisoning
Food poisoning usually brings diarrhea, vomiting, belly pain, fever and headache, lasting from a few hours to several days. Dehydration is the most common complication (NIDDK). Most cases of acute diarrhea get better on their own with fluids and electrolytes, such as water, broths and oral rehydration solutions (NIDDK).
What the evidence says about common fixes
Advice about stomach problems ranges from well established to wishful. This table rates some common claims by the strength of the evidence behind them.
| Claim | Evidence strength | Source |
|---|---|---|
| H. pylori and NSAIDs are the main causes of peptic ulcers | Strong | NIDDK |
| Antacids, H2 blockers and PPIs ease reflux symptoms | Strong | NIDDK |
| Eating at least 3 hours before lying down may ease night-time reflux | Moderate | NIDDK |
| A low FODMAP diet may ease IBS symptoms in some people | Moderate | NIDDK |
| Enteric-coated peppermint oil may improve IBS symptoms | Moderate (10 studies, 1,030 people) | NCCIH |
| Ginger may help nausea during pregnancy | Moderate | NCCIH |
| Yogurt cultures help people with lactose intolerance digest the lactose in yogurt | Good; summarized in a review | Savaiano, 2014 |
| Probiotics may ease IBS symptoms | Uncertain; strains and doses unclear | NCCIH |
| Ginger helps nausea after surgery or chemotherapy | Uncertain | NCCIH |
| Acupuncture helps IBS more than sham | Mixed | Our acupuncture guide |
Two notes on supplements. NCCIH reports that peppermint oil can cause heartburn, nausea and belly pain, which is why capsules are often enteric-coated (NCCIH). And probiotics carry more risk for people who are seriously ill or have weakened immune systems, so they should talk with a doctor first (NCCIH).
Practical steps for everyday stomach trouble
These steps are low-risk and drawn from NIDDK advice. They suit occasional symptoms. If you have any warning signs listed further down, see a doctor first.
Change how you eat
- Eat smaller, more frequent meals. This is a common suggestion for gas and is part of NIDDK diet advice for gastroparesis (NIDDK).
- Slow down and sit down. Eating slowly, not talking while eating, and avoiding straws, gum, hard candy and fizzy drinks all reduce swallowed air (NIDDK).
- Leave a gap before bed. If reflux bothers you at night, finish eating at least 3 hours before lying down (NIDDK).
- Raise the head of your bed. A foam wedge or extra pillows under the head and upper back that lift you 6 to 8 inches may reduce night reflux (NIDDK).
Find your trigger foods
Triggers differ from person to person. For functional dyspepsia, NIDDK lists fizzy drinks, wheat products, caffeine, fruit and fruit juices, and fatty or greasy foods as common ones (NIDDK). For reflux, the list includes citrus, tomatoes, alcohol, chocolate, coffee, high-fat foods, mint and spicy foods (NIDDK). Keeping a simple food and symptom diary for two weeks is a practical way to spot patterns before cutting out whole food groups.
If you add fiber for constipation or IBS, go slowly. NIDDK suggests increasing by 2 to 3 grams a day to limit gas and bloating, and notes that soluble fiber, found in oats, beans and fruit, seems more helpful for IBS (NIDDK). Drink more fluids as you add fiber (NIDDK).
Review your medicines
Regular NSAID use is one of the most common causes of stomach lining damage and ulcers (NIDDK). If you take pain relievers often, ask your doctor whether another option suits you. Over-the-counter reflux medicines can help, but NIDDK advises talking with a doctor if symptoms do not go away with them, and not using antacids every day without medical advice (NIDDK).
Look after stress and sleep
Because so many stomach problems involve the gut-brain connection, stress management is a real treatment, not an afterthought. For IBS, NIDDK lists more physical activity, less stress and enough sleep as helpful lifestyle changes, and doctors may recommend cognitive behavioral therapy or gut-directed hypnotherapy (NIDDK). For functional dyspepsia, relaxation, meditation or counseling may also be suggested (NIDDK).
When your stomach is upset right now
For a short bout of upset stomach with diarrhea, the priority is fluids and electrolytes. When your appetite returns, you can usually go back to your normal diet (NIDDK). Our guide to upset stomach remedies covers simple options for the first day or two.
Where gut bacteria and fermented foods fit
Bacteria are part of normal digestion. They live throughout the gut, help break down food, and in the large intestine they ferment leftover carbohydrates and make vitamin K (NIDDK). That fermentation is also where much of your gas comes from, which is why the same fiber that feeds helpful bacteria can cause bloating if you add it too fast.
Yogurt is a good example of bacteria helping digestion. Lactose intolerance happens when the small intestine makes too little lactase, the enzyme that breaks down milk sugar, so lactose reaches the colon and bacteria turn it into gas and fluid (NIDDK). The live cultures in yogurt carry their own lactase, which helps many lactose-intolerant people digest the lactose in yogurt without symptoms (Savaiano, 2014). We look at this more in Is Yogurt Good for Upset Stomach?
Probiotic supplements are a different story. NCCIH describes moderate-quality evidence that probiotics may lower the chance of diarrhea linked to antibiotics, while results for IBS are promising but too varied to say which strains help (NCCIH). Probiotics do not replace a diagnosis, so find out what is causing your symptoms first.
When to see a doctor
This guide is general information, not medical advice, and it cannot diagnose your symptoms. Get medical help right away if stomach symptoms come with any of these warning signs, drawn from NIDDK and the NHS:
- Pain in the chest, jaw, neck or arm, or shortness of breath (NIDDK)
- Sudden, severe belly pain that does not go away, or pain that suddenly gets much worse
- Vomiting blood, or vomit that looks like coffee grounds or is green
- Black, tarry stools or blood in your stool
- Trouble or pain when swallowing
- Weight loss without trying, or loss of appetite
- Yellow skin or eyes
- Signs of dehydration, such as extreme thirst, dark urine, dizziness or very little urine
- Being unable to poo or pass gas at all, or being unable to pee (NHS)
Make a regular appointment if stomach pain, bloating or indigestion does not go away or keeps coming back, if you feel a lump in your belly (NHS), or if heartburn keeps returning despite over-the-counter medicine (NIDDK). Older adults, pregnant women and people with weak immune systems should see a doctor sooner for food poisoning symptoms (NIDDK). If an infant or child has food poisoning symptoms, NIDDK advises calling a doctor, because diarrhea can dehydrate babies very quickly.
What is the most common cause of stomach problems?
Indigestion with no clear cause, called functional dyspepsia, is the most common diagnosis among people who see a doctor for indigestion (NIDDK). Infections, reflux, NSAIDs and H. pylori are other common causes.
Can stress cause stomach problems?
Feeling stressed is linked with a higher chance of indigestion (NIDDK), and stress plays a part in IBS, which involves the gut-brain connection. Stress management is part of standard care for both.
How long should stomach pain last before I see a doctor?
See a doctor if pain does not go away, keeps coming back, or comes with warning signs such as blood, black stools, vomiting or weight loss. Get emergency care for sudden, severe pain.
Is it normal to have gas every day?
Yes. Passing gas up to 25 times a day is considered normal (NIDDK). Talk with a doctor if gas comes with pain, weight loss or a change in bowel habits.
Can yogurt help an upset stomach?
Plain yogurt with live cultures is easier to digest than milk for many lactose-intolerant people. It is not a treatment for stomach disease, and some people with IBS find dairy a trigger.
More on stomach problems
- Upset Stomach Remedies: simple steps for a short-term upset stomach.
- Diet for Sensitive Stomach: food choices that are often easier on the gut.
- What to Eat when Stomach is Upset?: gentle foods for the first day or two.
- Acupuncture for Digestive Issues: what trials show for IBS, indigestion and constipation.
- Brat Diet: what the bland-food approach can and cannot do.
- Best Tea for Digestion: peppermint, ginger and other teas compared.
Sources
- Digestive Diseases Statistics for the United States (NIDDK)
- Your Digestive System and How It Works (NIDDK)
- Definition and Facts of Indigestion (NIDDK)
- Symptoms and Causes of Indigestion (NIDDK)
- Treatment of Indigestion (NIDDK)
- Eating, Diet, and Nutrition for Indigestion (NIDDK)
- Definition and Facts for GER and GERD (NIDDK)
- Symptoms and Causes of GER and GERD (NIDDK)
- Treatment for GER and GERD (NIDDK)
- Eating, Diet, and Nutrition for GER and GERD (NIDDK)
- Symptoms and Causes of Gas in the Digestive Tract (NIDDK)
- Treatment for Gas in the Digestive Tract (NIDDK)
- Symptoms and Causes of Gastritis and Gastropathy (NIDDK)
- Definition and Facts for Peptic Ulcers (NIDDK)
- Symptoms and Causes of Peptic Ulcers (NIDDK)
- Symptoms and Causes of Gastroparesis (NIDDK)
- Definition and Facts for Irritable Bowel Syndrome (NIDDK)
- Eating, Diet, and Nutrition for Irritable Bowel Syndrome (NIDDK)
- Treatment for Irritable Bowel Syndrome (NIDDK)
- Symptoms and Causes of Food Poisoning (NIDDK)
- Treatment of Diarrhea (NIDDK)
- Symptoms and Causes of Lactose Intolerance (NIDDK)
- Treatment for Constipation (NIDDK)
- Symptoms and Causes of Gallstones (NIDDK)
- Stomach ache (NHS)
- Peppermint Oil (NCCIH)
- Ginger (NCCIH)
- Probiotics: Usefulness and Safety (NCCIH)
- Savaiano DA. Lactose digestion from yogurt: mechanism and relevance (American Journal of Clinical Nutrition, 2014)
This article is for general information and is not medical advice. Talk to your doctor or a registered dietitian before changing your diet, supplements or medication, especially if you have a health condition.
