Springdale Mason Pediatrics

Diarrhea (Baby on Formula)


  • Diarrhea is the sudden increase in the number and looseness of stools
  • Diarrhea means 3 or more watery or very loose stools. Reason: 1 loose stool can be normal with changes in diet.
  • Most diarrhea is caused by a viral infection of the intestines.

Call or Return If

  • Blood in the diarrhea
  • Signs of dehydration occur
  • Diarrhea lasts over 2 weeks
  • You think your child needs to be seen
  • Your child becomes worse

About This Topic

Diarrhea Scale

  • Mild: 3-5 watery stools per day
  • Moderate: 6-9 watery stools per day
  • Severe: 10 or more watery stools per day
  • The main risk of diarrhea is dehydration.

Diarrhea in Formula-Fed Infants: How to Know

  • Formula-fed babies pass 1 to 8 stools per day during the first week. Then it starts to slow down to 1 to 4 per day. This lasts until 2 months of age.
  • The stools are yellow in color and thick like peanut butter.
  • Suspect diarrhea if the stools suddenly increase in number or looseness. If it lasts for 3 or more stools, the baby has diarrhea.
  • If the stools contain mucus, blood, or smells bad, this points to diarrhea.
  • Other clues to diarrhea are poor eating, acting sick or a fever.
  • After 2 months of age, most babies pass 1 or 2 stools per day. They can also pass 1 every other day. They no longer appear to have mild diarrhea.

Dehydration: How to Know

  • Dehydration means that the body has lost too much fluid. This can happen with vomiting and/or diarrhea. Mild diarrhea or mild vomiting does not cause this.
  • These are signs of dehydration:
  • Decreased urine (no urine in more than 8 hours) happens early in dehydration. So does a dark yellow color. If the urine is light straw colored, your child is not dehydrated.
  • Dry tongue and inside of the mouth. Dry lips are not helpful.
  • Dry eyes with decreased or absent tears
  • In babies, a depressed or sunken soft spot
  • Slow blood refill test: Longer than 2 seconds. First, press on the thumbnail and make it pale. Then let go. Count the seconds it takes for the nail to turn pink again. Ask your doctor to teach you this test.
  • Fussy, tired out or acting ill. If your child is alert, happy and playful, he or she is not dehydrated.
  • A child with severe dehydration becomes too weak to stand. They can also be very dizzy when trying to stand.


  • Virus (such as Rotavirus). An infection of the intestines from a virus is the most common cause. It's called viral gastroenteritis.
  • Bacteria (such as Salmonella). Less common cause. Diarrhea often contains streaks of blood.
  • Food-poisoning. This causes rapid vomiting and diarrhea within hours after eating the bad food.

Prevention of Spread to Others

  • Careful hand washing after using the toilet or changing diapers.

After Care Advice

  • Most diarrhea is caused by a virus.
  • Diarrhea is the body's way of getting rid of the germs.
  • Your job is to prevent dehydration.
  • Here is some care advice that should help.
Mild Diarrhea:
  • Keep on a normal diet.
  • Offer more formula.
  • Do not give any fruit juices. Reason: They make diarrhea worse.
  • If on baby foods, offer more starchy foods (such as cereal, crackers, rice).
Frequent, Watery Diarrhea:
  • Keep giving formula but feed more often. Offer as much formula as your baby will take.
  • Mix formula the normal way. Reason: It contains plenty of water and doesn't need more.
  • Solid foods: If on baby foods, continue them. Cereals are best.
Oral Rehydration Solutions (ORS) such as Pedialyte to Prevent Dehydration:
  • ORS is a special fluid that can help your baby stay hydrated. You can use Pedialyte or the store brand. It can be bought in food stores or drug stores.
  • When to use: Start ORS for frequent, watery diarrhea if you think your baby is getting dehydrated. That means passing less urine than normal. Increase fluids using ORS. Also continue giving formula.
  • Amount for babies: Give 2-4 ounces (60-120 ml) of ORS after every large watery stool.
  • Caution: Do not give ORS as the only fluid for more than 6 hours. Reason: Your baby will need calories and cry in hunger.
Going Back to Formula:
  • Go back to formula by 6 hours at the latest. Reason: Your baby needs the calories.
  • Use formula mixed the normal way. Reason: It contains plenty of water.
  • Offer the formula more often than you normally do.
  • Soy formula: Regular formula is fine for most diarrhea. Lactose-free formula (soy formula) is only needed for watery diarrhea lasting over 3 days.
  • Extra ORS: Also give 2-4 ounces (60-120 ml) of ORS after every large watery stool. (Especially if the urine is dark).
Solid Foods:
  • Babies over 4 months old: Keep on baby foods. If diarrhea is bad, start with cereals.
  • Go back to a normal diet in 24 hours.
Diaper Rash:
  • Wash buttocks after each stool to prevent a bad diaper rash. It may be necessary to get up once during the night to change the diaper.
  • To protect the skin, use an ointment (such as petroleum jelly). Put it on the skin around the anus.
What to Expect:
  • Viral diarrhea lasts 5-14 days.
  • Severe diarrhea only occurs on the first 1 or 2 days. But, loose stools can last for 1 to 2 weeks.
Return to Child Care:
  • Your child can go back to child care after the stools are formed.
  • The fever should also be gone.

Author: Barton Schmitt MD, FAAP
Copyright 2000-2021 Schmitt Pediatric Guidelines LLC
Disclaimer: This health information is for educational purposes only. You the reader assume full responsibility for how you choose to use it.
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