Bacterial Diarrhea (Adult)

Gastroenteritis is an infection in the intestinal tract. It is sometimes called the "stomach flu" but it is not related to influenza. Although most diarrhea is caused by a virus, you have a bacterial infection. It causes diarrhea. Diarrhea is the passing of loose watery stools 3 or more times a day.

Antibiotics are often used to treat this type of infection. Sometimes it is necessary to wait until a stool culture is complete before an antibiotic can be chosen. This may take about 2 days. Certain types of gastroenteritis should not be treated with antibiotics. Such treatment can lead to other problems. Because of this, don't take antibiotics until your provider has the results of your stool culture and advises an appropriate antibiotic.

Along with diarrhea, you may have these symptoms:

  • Belly (abdominal) pain and cramping

  • Nausea and vomiting

  • Loss of bowel control

  • Fever and chills

  • Bloody stools

The main danger of diarrhea is dehydration. Dehydration is the loss of too much water and other fluids from the body without taking in enough fluids to replace it. When this occurs, body fluids must be replaced with oral rehydration solutions. These solutions are available at pharmacies and most grocery stores without a prescription. 

Home care


  • If antibiotics were prescribed, be sure you take them as directed until they are finished. Keep taking the antibiotics as prescribed even if your symptoms go away and you feel better.

  • You may use acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen to control fever, unless another medicine was prescribed. If you have chronic liver or kidney disease or ever had a stomach ulcer or gastrointestinal bleeding, talk with your healthcare provider before using these medicines. Aspirin should never be used in anyone under 18 years of age who is ill with a fever. It may cause severe liver damage. Don't increase your use of NSAID medicines if you are already taking the medicine for another condition (such as arthritis). Don't use NSAIDs if you are on daily aspirin therapy (such as for heart disease or after stroke).

  • Don't take over-the-counter anti-diarrheal medicines, unless advised by your healthcare provider. They can make your bacterial diarrhea worse. This is especially true if you have a fever or the diarrhea is bloody.

Prevent spread of the illness

  • If symptoms are severe, rest at home for the next 24 hours or until you are feeling better.

  • Wash your hands with soap and water or use alcohol-based sanitizer after touching anyone who is sick, after using the toilet, and before meals.

  • Teach all people in your home when and how to wash their hands. Wet your hands with clean, running water and lather the backs of your hands, between your fingers, and under your nails. Scrub your hands for at least 20 seconds. If you need a timer, try humming the “Happy Birthday” song from beginning to end twice. Rinse your hands well and dry them with a clean towel.

  • Clean the toilet after each use.

  • Don't prepare or serve food to others.


  • To prevent dehydration, sip water and clear liquids, soft drinks without caffeine, ginger ale, mineral water, decaf tea and coffee. Drink small amounts at a time, don't guzzle it. Sports drinks are not a good choice because they have too much sugar and not enough electrolytes. Commercially available oral rehydration solutions are best.

  • If you eat, don't have fatty, greasy, spicy, or fried foods.

  • Don't eat or drink dairy products if you have diarrhea, as they can make diarrhea worse.

  • Caffeine, tobacco, and alcohol can make the diarrhea, cramping, and pain worse. Remember, caffeine is in coffee, chocolate, colas, some energy drinks, and teas. Try to stop using these substances until you have recovered.

  • Don't force yourself to eat, especially if having cramping, vomiting, or diarrhea. Don't eat large amounts at a time, even if you are hungry

During the first 24 hours (the first full day), follow the diet below:

  • Beverages: Water, clear liquids, soft drinks without caffeine; ginger ale, mineral water (plain or flavored), decaffeinated tea and coffee. Avoid sports drinks.

  • Soups: Clear broth, consommé and bouillon

  • Desserts: Plain gelatin, ice pops, and fruit juice bars.

During the next 24 hours (the second day) you may add these to the diet above if you have improved:

  • Hot cereal, plain toast, bread, rolls, crackers

  • Plain noodles, rice, mashed potatoes, chicken noodle or rice soup

  • Unsweetened canned fruit like applesauce and bananas (stay away from pineapple and citrus)

  • Limit fat intake to less than 15 grams per day by skip margarine, butter, oils, mayonnaise, sauces, gravies, fried foods, peanut butter, meat, poultry and fish.

  • Limit dairy.

  • Limit fiber; don't eat raw or cooked vegetables, fresh fruits (except bananas) and bran cereals.

  • Limit caffeine and chocolate. No spices or seasonings except salt.

During the next 24 hours:

  • Slowly go back to a normal diet, as you feel better and your symptoms lessen.

  • If at any time your symptoms get worse, go back to clear liquids until you feel better.

Follow-up care

Follow up with your healthcare provider as advised. Call if you are not improving within 24 hours or if the diarrhea lasts more than 1 week on antibiotics. If a stool (diarrhea) sample was taken, you may call in 2 days (or as directed) for the results.

When to get medical advice

Call your healthcare provider right away if any of the following occur:

  • Increasing belly pain or constant lower right belly pain

  • Continued vomiting (unable to keep liquids down)

  • Frequent diarrhea (more than 5 times a day)

  • Blood in vomit or stool (black or red color)

  • Reduced oral intake

  • Dark urine, reduced urine output

  • Weakness, dizziness

  • Drowsiness

  • Fever of 100.4ºF (38ºC) or higher, or as directed by your healthcare provider

  • New rash

  • Symptoms get worse or you have new symptoms

High-risk groups

Some people are more prone to risks from diarrhea, like dehydration. These people include the very elderly, those with weak immune systems (for cancer treatment, for example), or those who have inflammatory bowel disease (Crohn's or colitis). If you are in one of these groups, see your healthcare provider right away if your diarrhea symptoms get worse or don't improve with treatment.

Call 911

Call 911 if any of the following occur:

  • Trouble breathing

  • Confused

  • Severe drowsiness or trouble awakening

  • Fainting or loss of consciousness

  • Rapid heart rate

  • Seizure

  • Stiff neck

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