What to Do About Red Stools in Babies

Omnicef is a popular antibiotic for ear infections in babies, but it may cause red stools. The question is whether or not what you're seeing is blood or something else.

Baby getting a diaper change
Science Photo Library - RUTH JENKINSON / Getty Images

Antibiotic Side Effects

Bloody stools can be a complication of being on antibiotics.

Being on antibiotics can cause an infection of the intestinal tract called Clostridioides difficile (C. difficile or C. diff). Other symptoms usually include abdominal pain, weight loss, diarrhea (often bloody), fever and decreased appetite.

Omnicef and Red Stools

However, if your baby is feeling better, infection with C. difficile is unlikely.

Instead, your child is probably just having a common side effect that notoriously happens to kids who take Omnicef (cefdinir), which is having orange, maroon, or red-colored stools. Supposedly this happens because of the way Omnicef interacts with iron in your child's diet (typically an infant who is drinking an iron-fortified formula).

Specifically, one of cefdinir's "metabolites may bind to ferric ions, forming a nonabsorbable complex that imparts a reddish color to the stool."

Fortunately, the reddish color goes away once your child finishes the course of antibiotics.

Is It Blood?

Still, it is probably not safe to just assume that the red stool isn't really caused by blood. Instead, call your healthcare provider and ask if you can bring in a dirty diaper to have it tested. This is a simple test that your pediatrician should be able to do in their office (stool guaiac test). If the stool test doesn't show any blood in the red stools, then you can likely continue the Omnicef.

Since Omnicef is becoming more widely used because of its good taste, once a day dosing, and effectiveness against stubborn ear infections, it is important to be aware of this possible side effect.

Also, remember that you should always talk with your pediatrician before stopping any medication that has been prescribed to your child.

And this is also a good reason to follow the latest antibiotic prescribing guidelines and only take an antibiotic when your child really needs it, especially avoiding prescriptions for viral infections.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Graves R. Cefdinir-associated “bloody stools” in an infant. J Am Board Fam Med. 2008;21:246–248 DOI: 10.3122/jabfm.2008.03.070242

  2. Lancaster J. Nonbloody, red stools from coadministration of cefdinir and iron-supplemented infant formulas. Pharmacotherapy. 2008;28:678–681 doi: 10.1592/phco.28.5.678

  3. Roath MC, Di Palma JA. Correspondence: cefdinir and red stool. Gastroenterol Hepatol (N Y). 2013;9(6):338. PMID: 23935540

By Vincent Iannelli, MD
 Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.