7 Side Effects of Amoxicillin You Should Know About

Over the years, amoxicillin has been recommended as a first-choice antibiotic for several illnesses. It’s widely available across the U.S., and it’s pretty affordable, too. 

In general, amoxicillin is well-tolerated. But like with all medications, it has a number of side effects, varying from mild and manageable to those that are a bit more serious. So if you or your child have been prescribed amoxicillin for a bacterial infection, it’s best to be aware of the possible risks. 

What is amoxicillin?

Amoxicillin is an FDA-approved prescription antibiotic. It treats many types of bacterial infections in children and adults, such as:

• Ear, nose, and throat infections, including strep throat

• Urinary tract infections (UTIs)

• Lower respiratory tract infections

• Skin infections

• Helicobacter pylori infections (adults only) 

Amoxicillin is also relatively easy to take. It’s typically taken by mouth 2 to 3 times per day for a short period of time. It comes as tablets, capsules, and chewable tablets. An oral suspension (liquid) is also available.

You may have also heard of amoxicillin being used in combination with an antibiotic called clavulanate. The combination treats many of the same bacterial infections as amoxicillin by itself, but clavulanate helps amoxicillin work better against certain bacteria. This combination is better known by its brand name — Augmentin.

How does amoxicillin work?

Amoxicillin belongs to a group of medications called penicillin antibiotics. Amoxicillin is a type of penicillin antibiotic because it contains a chemical structure called a beta-lactam ring, which penicillin also has. The beta-lactam ring helps kill bacteria so your body can start to recover. 

7 amoxicillin side effects to know about

Amoxicillin is generally well-tolerated. But it still has some side effects you should be aware of. 

Most side effects are manageable, temporary, and go away after you finish the antibiotic. But some can become severe and require assistance from a healthcare provider. 

To help prevent and control these risks, it’s recommended to talk with your healthcare provider about amoxicillin side effects before you start taking it. To get the conversation started, here are seven amoxicillin side effects to keep in mind.

1. Nausea

Nausea is one of the most common amoxicillin side effects. But it’s usually mild when it happens. Taking it with food can help lessen or prevent this unpleasant side effect. There are also over-the-counter (OTC) medications available to help manage nausea, such as Dramamine (dimenhydrinate) and Bonine (meclizine). 

2. Vomiting

Nausea and vomiting tend to go hand-in-hand. Vomiting is also one of the more common amoxicillin side effects. 

Taking amoxicillin with food can help prevent and control vomiting. You may also consider trying an electrolyte drink — like Pedialyte or Gatorade — if you experience vomiting. This can help replenish electrolytes that your body may have lost. 

If you or a loved one vomits soon after taking amoxicillin, contact your healthcare provider about what to do next. Whether you need to take another dose depends on certain factors, like how soon you threw up after taking your last amoxicillin dose. 

Amoxicillin Capsule

3. Diarrhea

Diarrhea is another common side effect of antibiotics like amoxicillin. Augmentin has been reported to cause diarrhea more often than amoxicillin alone, but it’s still possible with just amoxicillin. 

Amoxicillin generally causes mild diarrhea. But taking amoxicillin with food can help prevent it from happening in the first place. You can also try using the BRAT diet to manage mild diarrhea. This is an acronym that stands for bananas, rice, applesauce, and toast, which are foods that are gentle on your stomach. Electrolyte drinks and water are also helpful for hydration.

When needed, OTC medications for diarrhea can also act as a source of relief. Imodium A-D (loperamide) is one popular option to consider. 

In rare cases, diarrhea can become severe. Antibiotics like amoxicillin can contribute to severe, infectious diarrhea that requires immediate medical attention. This is known as Clostridioides difficile (“C. diff”) diarrhea. Symptoms of this include:

• Severe diarrhea

• Nausea

• Stomach pain or tenderness

• Loss of appetite

• Fever  

4. Skin rash

It can be scary to notice a rash after starting a medication. But rashes are another common side effect of amoxicillin. In fact, they can happen in up to 10% of people who take it. 

Thankfully, these rashes aren’t usually serious. They tend to go away after a few days. A typical amoxicillin rash looks like flat, red patches on the skin. Benadryl (diphenhydramine) and hydrocortisone cream are OTC medications that can help manage skin rashes. 

However, if you experience hives — raised, itchy bumps — this could be the sign of an allergic reaction (allergic skin rash). We’ll discuss allergic reactions more below.

5. Headache

It can be frustrating to experience headaches. Most medications — including amoxicillin — have the potential to cause headaches to some degree. 

Thankfully, with amoxicillin, headaches are typically minor and go away after finishing your treatment. When needed, OTC medications like Tylenol (acetaminophen) can help manage headaches. 

6. Taste and smell changes

Some people have experienced a metallic or sour taste in their mouth while taking amoxicillin in clinical studies. Similar taste and smell changes have also been reported to the FDA by some people. 

This side effect may seem alarming, but it isn’t thought to be permanent. Your taste and smell should return to normal after you finish your course of amoxicillin.  

7. Allergic reactions

Allergic reactions are a common concern with amoxicillin. About 10% of people have reported an allergic reaction to penicillin antibiotics, which includes amoxicillin. But only about 1% actually have a true allergy. 

Skin rashes involving hives are one common sign of an allergy. Other possible signs of a penicillin allergy include wheezing, throat tightness, or a fast heartbeat. 

Also keep an eye out for signs of anaphylaxis, which includes trouble breathing or swelling of the face, tongue, or throat. Anaphylaxis is a medical emergency caused by a severe allergic reaction. It’s important to seek emergency treatment right away if you or a loved one are experiencing anaphylaxis. 

When should I contact my healthcare provider about side effects from amoxicillin?

You should contact your healthcare provider if you experience any side effects that are bothering you or don’t go away. But if you experience any of these side effects, a call to your healthcare provider may be especially warranted:

• Nausea, vomiting, or diarrhea that’s severe or won’t go away

• A headache that’s severe or won’t go away

• Stomach pain or tenderness

• Signs of an allergic reaction

If you experience trouble breathing or signs of facial swelling, it’s better to call 911 or seek medical attention right away. This is likely a sign of a more serious allergic reaction.