Diagnosis

Your healthcare professional will likely ask about your medical history, review the medicines you take and conduct a physical exam. Your health professional may order tests to determine what's causing your diarrhea. Possible tests include:

  • Blood tests. A complete blood count, measurement of electrolytes and tests of kidney function can help indicate how bad your diarrhea is.
  • Stool test. You may have a stool test to see if a bacterium or parasite is causing your diarrhea.
  • Hydrogen breath test. This type of test can help determine if you have a lactose intolerance. After you drink a liquid that contains high levels of lactose, your breath is measured for hydrogen at regular intervals. Breathing out too much hydrogen indicates that you aren't fully digesting and absorbing lactose.
  • Flexible sigmoidoscopy or colonoscopy. Using a thin, lighted tube that's inserted into the rectum, a medical professional can see inside of the colon. The device also has a tool that allows the doctor to take a small sample of tissue, called a biopsy, from the colon. Flexible sigmoidoscopy provides a view of the lower colon, while colonoscopy allows the doctor to see the entire colon.
  • Upper endoscopy. A medical professional uses a long, thin tube with a camera on the end to examine the stomach and upper small intestine. They may remove a tissue sample to be checked in a laboratory.

Treatment

Most cases of sudden diarrhea clear on their own within a couple of days without treatment. If you've tried lifestyle changes and home remedies for diarrhea without success, your healthcare professional might recommend medicines or other treatments.

Antibiotics or antiparasitics

Antibiotics or antiparasitic medicines might help treat diarrhea caused by certain bacteria or parasites. Most bacterial causes of diarrhea do not need treatment in most people. If a virus is causing your diarrhea, antibiotics won't help.

Treatment to replace fluids

Your healthcare professional likely will advise you to replace the fluids and salts that you lose when you have diarrhea. For most adults, that means drinking water with electrolytes, juice or broth. If drinking liquids upsets your stomach or causes vomiting, your healthcare professional might give you IV fluids.

Water is a good way to replace fluids, but it doesn't contain the salts and electrolytes — minerals such as sodium and potassium — that your body needs to function. You can help maintain your electrolyte levels by drinking fruit juices for potassium or eating soups for sodium. But certain fruit juices, such as apple juice, might make diarrhea worse.

For children, ask your doctor about using an oral rehydration solution, such as Pedialyte, to prevent dehydration or replace lost fluids.

Adjusting medicines you're taking

If your healthcare professional determines that an antibiotic caused your diarrhea, you might be given a lower dose or a different medicine.

Treating underlying conditions

If your diarrhea is caused by a more serious condition, such as inflammatory bowel disease, your healthcare professional works to control that condition. You might be referred to a specialist, such as a gastroenterologist, who can help devise a treatment plan for you.

Lifestyle and home remedies

Diarrhea usually clears up quickly without treatment. To help you cope with your symptoms until the diarrhea goes away, try to do the following:

  • Drink plenty of liquids, including water, broths and juices. Avoid caffeine and alcohol.
  • Add semisolid and low-fiber foods gradually as your stool returns to what's typical for you. Try soda crackers, toast, eggs, rice or chicken.
  • Don't eat certain foods such as dairy products, fatty foods, high-fiber foods or highly seasoned foods for a few days.

  • Ask about antidiarrheal medicines. Nonprescription antidiarrheal medicines, such as loperamide and bismuth subsalicylate, might help reduce how often you pass watery stool and control severe symptoms.

    Certain medical conditions and infections — bacterial and parasitic — can be worsened by these medicines because they prevent your body from getting rid of what's causing the diarrhea. Some of these medicines are not recommended for children. Check with your healthcare professional before taking these medicines or giving them to a child.

  • Take probiotics. These microorganisms may help restore a healthy balance to the intestinal tract by boosting the level of good bacteria. However, it's not clear if they can help shorten a bout of diarrhea. Probiotics are available in capsule or liquid form and are also added to some foods, such as certain brands of yogurt. Further research is needed to better understand which strains of bacteria are most helpful and what doses are needed.

Preparing for your appointment

You might start by seeing a member of your primary healthcare team. If you have lasting diarrhea, you may be referred to a doctor who specializes in the digestive system, called a gastroenterologist.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fast before certain tests. Make a list of:

  • Your symptoms, including when they began and any that may seem unrelated to the reason for your appointment.
  • Key personal information, including any major stresses, recent life changes or travel.
  • Medicines, vitamins or supplements you take, including doses. If you've recently taken an antibiotic, note what kind, for how long and when you stopped.
  • Questions to ask your healthcare professional.

For diarrhea, some basic questions to ask include:

  • What is likely causing my diarrhea?
  • Could my diarrhea be caused by a medicine I'm taking?
  • What tests do I need?
  • Is my diarrhea likely short-term or long lasting?
  • What is the best course of action?
  • What are the alternatives to the primary approach that you're suggesting?
  • I have other health conditions. How can I best manage them with the diarrhea?
  • Are there restrictions I should follow?
  • May I take medicine such as loperamide to slow down the diarrhea?
  • Should I see a specialist?

Don't hesitate to ask other questions.

What to expect from your doctor

Your healthcare professional is likely to ask you questions, including:

  • When did your symptoms begin?
  • Do your symptoms happen all the time or only sometimes?
  • How bad are your symptoms?
  • What, if anything, seems to make your symptoms better?
  • What, if anything, appears to make your symptoms worse?
  • Does your diarrhea awaken you at night?
  • Do you see blood in your stool, or are your stools black?
  • Have you recently been around anyone who has diarrhea?
  • Have you recently stayed in a hospital or nursing home?
  • Have you taken antibiotics recently?

What you can do in the meantime

While you wait for your appointment, you may ease your symptoms if you:

  • Drink more fluids. To help avoid dehydration, drink water, juice and broth.
  • Don't eat foods that can aggravate diarrhea. Stay away from fatty, high-fiber or highly seasoned foods.
By Mayo Clinic Staff