Why Do We Vomit When We Get Sick?

Vomiting is one of the most unpleasant symptoms we have to endure when we get certain illnesses. Although it is most commonly caused by gastroenteritis (sometimes called “stomach flu”), people also deal with vomiting during pregnancy, after taking certain medications, while undergoing cancer treatments, when they have migraine headaches, and several other reasons.

We will look at what happens to our bodies when we vomit. Why does it occur and what can we do to feel better?

A girl vomiting into a bucket
Image Source / Getty Images

What Causes Vomiting?

When we are sick with an illness that leads to vomiting, the lining of the gastrointestinal (GI) tract is typically inflamed and irritated. When you try to eat or drink, you further irritate that lining, causing it to expel the contents of your stomach. Sometimes the irritation is so bad or your reflex is so sensitive that it causes the continuation of the vomiting even after your stomach is empty. You may vomit bile or you may just “dry heave.”

Vomiting can also be caused by issues with the brain—such as a concussion/head injury, brain tumor, migraine headache or infection, or with the inner ear, such as dizziness or motion sickness. In these cases, vomiting occurs without any irritation of the GI tract.

In adults and older children, the most common cause of vomiting is viral gastroenteritis.

What You Can Do

If you find yourself dealing with vomiting—whether it is yourself or someone you care for—there are things you should know about how to treat it. Although it is only a symptom of an illness and not an illness itself, the actions you take when you are vomiting can affect how quickly you recover and how bad it may be.

This article on vomiting treatments will take you through step-by-step instructions on what to do when you or someone you are caring for is vomiting. It can also help you figure out when you might be in a situation where you need to seek medical attention.

One of the most important lessons you will learn—and something that many people make the mistake of doing without knowing how much it can harm—is not to eat or drink anything immediately after vomiting. It can be tempting to at least drink something after you throw up because your mouth now tastes horrible and you want to avoid dehydration, but eating or drinking right after vomiting often leads to more vomiting. If your stomach is emptying itself, it needs time to rest and relax before you put anything else in it. Wait at least 15 minutes before you try to eat or drink after vomiting.

There are mixed reviews about whether or not following a strict BRAT diet will help with vomiting and/or diarrhea. In general, letting your stomach rest and eating bland starchy foods for a day or two after vomiting (or while you are recovering) isn’t going to hurt. These foods are gentler on the stomach and less likely to irritate your GI system. If you are unable to eat foods that are included in the BRAT diet, talk with your healthcare provider or dietitian about alternatives.

When to Seek Help

Sometimes, vomiting is so severe that it can’t be managed at home or it is caused by something serious that needs medical treatment. Figuring out if one of these situations applies to you can be difficult. If you are vomiting multiple times a day for more than about 24 hours, it’s a good idea to contact your healthcare provider.

You should also seek medical attention if you are vomiting blood or if your vomit looks like coffee grounds. If you experience a severe headache and stiff neck or neck pain with vomiting, contact your healthcare provider right away.

If you aren’t sure what to do, always contact your healthcare provider for advice.

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. National Institute of Diabetes and Digestive and Kidney Diseases. Viral gastroenteritis (“stomach flu”).

  2. American Academy of Family Physicians. BRAT diet: recovering from an upset stomach.

  3. Laine L, Laursen SB, Zakko L, et al. Severity and outcomes of upper gastrointestinal bleeding with bloody vs. coffee-grounds hematemesis. Am J Gastroenterol. 2018;113(3):358-366. doi:10.1038/ajg.2018.5

By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.