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Diarrhea: Formula-fed Infants

What is diarrhea?

Diarrhea is the sudden increase in the frequency and looseness of stools. Mild diarrhea is the passage of a few loose or mushy stools. Severe diarrhea is the passage of many watery stools. The best indicator of the severity of the diarrhea is its frequency.

The main complication of diarrhea is dehydration from the loss of too much fluid from the body. Symptoms of dehydration are a dry mouth, the absence of tears, infrequent urination (for example, none in 8 hours), and a darker, concentrated urine. The main goal of diarrhea treatment is to prevent dehydration.

What is the cause?

Diarrhea is usually caused by a viral infection of the lining of the intestines (gastroenteritis). Sometimes it is caused by bacteria or parasites. Occasionally a food allergy or drinking too much fruit juice may cause diarrhea. If your child has just one or two loose stools, the cause is probably something your child ate. A diet of nothing but clear fluids (such as Pedialyte) for more than 2 days may cause green, watery stools (called "starvation stools").

How long will it last?

Diarrhea caused by a viral infection usually lasts several days to 2 weeks, regardless of the type of treatment. The main goal of treatment is to prevent dehydration. Your child needs to drink enough fluids to replace the fluids lost in the diarrhea. Don't expect a quick return to solid stools.

What should I feed my child?

Increased fluids and dietary changes are the main treatment for diarrhea.

Note: One loose stool can mean nothing. Don't start dietary changes until your child has had several loose stools.

Mild diarrhea (loose stools)

Continue a regular diet with a few simple changes. Give full-strength formula—as much as your baby wants. If your baby eats solid foods, offer more rice cereal, mashed potatoes, strained bananas, and strained carrots. Avoid all fruit juices because they make diarrhea worse.

Frequent, watery diarrhea

  • Oral glucose-electrolyte solutions for 4 to 6 hours

    If your child has severe watery diarrhea and dark urine or not much urine, buy Pedialyte or the store brand at your pharmacy or supermarket. (These special solutions are not needed for diarrhea that is not severe.) Give as much of the special liquid as your baby wants (at least 2 teaspoons or 10 ml for every pound your child weighs each hour). Diarrhea makes children thirsty, and your job is to satisfy that thirst and prevent dehydration. Never restrict fluids when your child has diarrhea.

    Until you get one of these special solutions, continue giving your baby full-strength formula in unlimited amounts. Avoid giving your baby fruit juice because it will make the diarrhea worse.

  • Returning to formula

    After being given electrolyte fluids for 4 to 6 hours, your baby will be hungry, so begin her full-strength formula. Offer it more often than you normally do. If the diarrhea continues to be severe and doesn't improve after 3 days, change to a soy formula. Often there is less diarrhea with soy formulas than with cow's milk formulas because the soy formulas don't contain milk sugar (lactose). If you need to start soy formula, plan to keep your baby on it until the diarrhea is gone for 3 days.

  • Continuing solid foods

    Foods that contain a lot of starch are more easily digested than other foods during diarrhea. If your baby is over 4 months old, continue solid foods. Good choices are cereals and other high-fiber foods. Strained bananas, strained carrots, and mashed potatoes are also good.

How can I take care of my child?

There is no effective, safe drug for diarrhea. Extra fluids and diet therapy work best.

  • Common mistakes

    Using boiled skim milk can cause serious complications for babies with diarrhea because it contains too much salt. Use only the fluids suggested here.

    Do not dilute your baby's formula or give only clear fluids. This will not provide your baby with enough calories.

    The most dangerous myth is that the intestine should be "put to rest." Restricting fluids can cause dehydration.

    There is no effective, safe drug for diarrhea. Extra fluids and diet therapy work best.

  • Prevention

    Diarrhea can be very contagious. Always wash your hands after changing diapers or using the toilet. This is crucial for keeping everyone in the family from getting diarrhea.

  • Diaper rash from diarrhea

    The skin near your baby's anus can become irritated by the diarrhea. Wash the area near the anus after each stool and then protect it with a thick layer of petroleum jelly or other ointment. This protection is especially needed during the night and during naps. Changing the diaper quickly after stools also helps. It may be necessary to get up once during the night to change the diaper.

  • Overflow diarrhea in a child not toilet-trained

    For children in diapers, diarrhea can be a mess. Place a cotton washcloth inside the diaper to trap some of the more watery stool. Use diapers with snug leg bands or cover the diapers with a pair of plastic pants. Wash your child under running water in the bathtub.

  • Vomiting with diarrhea

    If your child has vomited more than twice, follow your doctor's recommended treatment for vomiting instead of this treatment for diarrhea until your child has gone 8 hours without vomiting. A good approach is for your child to take one swallow of fluid at a time every 5 minutes. (See information on vomiting.)

When should I call my child's healthcare provider?

Call IMMEDIATELY if:

  • There are signs of dehydration (no urine in more than 8 hours, very dry mouth, no tears).
  • Any blood appears in the diarrhea.
  • The diarrhea is severe (more than 8 stools in the last 8 hours).
  • The diarrhea is watery AND your child repeatedly vomits.
  • Your child starts acting very sick.

Call during office hours if:

  • Mucus or pus appears in the stools.
  • A fever lasts more than 3 days.
  • Mild diarrhea lasts more than 2 weeks.
  • You have other concerns or questions.
Written by Barton D. Schmitt, MD, author of “My Child Is Sick,” American Academy of Pediatrics Books.
Pediatric Advisor 2018.1 published by Change Healthcare.
Last modified: 2016-06-01
Last reviewed: 2017-06-05
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2018 Barton D. Schmitt, MD FAAP. All rights reserved.
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