The Most Common Amoxicillin Side Effects in Babies

Amoxicillin treats a host of bacterial infections, such as pneumonia and ear infections. While deemed safe for babies, amoxicillin side effects are common.


Amoxicillin was my saving grace when my kids were babies. It worked quickly to ease discomfort and due to its tolerable bubble gum-like taste, was the only medicine my little ones would gladly slurp down without resistance.

Nearly 28 amoxicillin prescriptions were written in 2014, according to the Medical Expenditure Panel Survey (MEPS). The antibiotic is safe for use by most children. However, like all medications, there is a risk for side effects when taking the drug.

Remember that amoxicillin is not a one-size-fits-all medicine.

“Antibiotics are only effective against bacteria, which means they’re useless against ailments like the flu and colds,” says Iona Munjal, M.D. of The Children’s Hospital in Bronx, New York.

Before beginning treatment, talk to your child’s pediatrician about your concerns regarding potential side effects and how to reduce your child’s risk of complications.

What the Experts Say

“The most common side effects your child is likely to face when on antibiotic therapy are nausea, vomiting, and diarrhea. To reduce the risk of these side effects, follow the food and drink advice on the medication bottle’s label.”

Meals That Heal for Babies and Toddlers, Eileen Behan


“Amoxicillin is widely used in children for other indications in whom diarrhea, gastrointestinal discomfort, and rashes are common side effects, and anaphylactic reactions occur in 0.01% of patients.”

Handbook of Child and Adolescent Tuberculosis, Jeffrey R. Starke, Peter R. Donald


“Penicillins pass into the breast milk. Even though small amounts may pass into breast milk, allergic reactions, diarrhea, fungus infections, and skin rash may occur.”

Advice for the Patient Drug Information in Lay Language, United States Pharmacopeial Convention


Common Side Effects

Our children are exposed to bacteria every day. Bacteria lives on the skin, find harbor in our intestines, and exist on nearly every surface. While most adults have the immune system strength needed to fight off harmful bacteria, the immune systems in babies are far less resilient.

Amoxicillin is used in the treatment and prevention of bacterial infections to either inhibit or kill bacteria growth. Some babies may experience side effects as a result of the medication.

Approximately 1 in 5 patients suffers from antibiotic side effects, according to a John Hopkins Medicine study published in JAMA Internal Medicine journal.

Common side effects of amoxicillin in babies include:

  • Diarrhea: One of the most common side effects of amoxicillin in babies is diarrhea. In a study involving 240 children who were treated for acute otitis media with amoxicillin, 17 percent experienced diarrhea on day four, according to BMJ Publishing Group.
  • Skin Rash: Some children may develop a harmless skin rash caused by amoxicillin treatment. A rash does not mean that your baby has an allergy to the penicillin drug. Instead, an allergic reaction would cause hives or more serious symptoms.
  • Vomiting: Nausea and vomiting are both common symptoms of amoxicillin. The drug can cause your little one to throw up shortly after taking a dose. While the vomiting is likely temporary, it’s important to contact your child’s pediatrician if an upset stomach continues.
  • Diaper Rash: Similar to a regular skin rash, babies are vulnerable to diaper rash caused by amoxicillin. Antibiotics can result in several types of diaper rash, including contact diaper rash caused by contact with loose stools, and fungal diaper rash that occurs from an overgrowth of yeast in the intestines.

Drug Precautions

Amoxicillin is not right for all babies. Tell your child’s pediatrician or pharmacist if your child has certain conditions that could negatively interact with the drug, such as kidney disease, asthma, stomach or intestinal disease, or phenylketonuria (PKU).

Be sure to follow all medication guidelines before giving your child amoxicillin. Do not stop administering the medication until your child’s pediatrician or pharmacist tells you to, even if your child seems to be feeling better.

Give your baby the medicine at the same times each day and do not miss any doses. Before giving your baby liquid amoxicillin, shake the bottle well and measure the dose accurately with a syringe or measuring spoon.

Most babies begin to feel better within a few days after starting amoxicillin. If your little one continues to experience mild side effects like diarrhea or rash, or if more serious side effects occur like hives or unusual weakness, contact your baby’s pediatrician.


Brandy Dishaw

Brandy is a content specialist and proud mother of two children. She enjoys writing engaging content on parenting, children’s health, and educational topics, and has been published on websites like Modern Mom, Yahoo! Shine, and With more than a decade of experience as a writer and mom, she combines research and personal experience to provide her audience with insight to the world of parenting.

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