How to Get Rid of Stomach Pain After Eating Pizza
Health ConditionsDigestive Health

5 Potential Reasons Pizza Makes You Feel Sick

5 Potential Reasons Pizza Makes You Feel Sick
Svitlana Lushko/iStock
By
Kathleen Ferraro
Updated on August 6, 2025
by

Pizza is a beloved food to many people for good reason — it's delicious. But for some people, eating a slice can lead to digestive discomfort.

Here are five potential reasons you may not feel well after eating pizza and what you can do about them.

1. You’re Lactose Intolerant

One reason your stomach may hurt after eating pizza is that you’re lactose intolerant. Lactose intolerance occurs when your body doesn’t produce enough lactase, the enzyme that breaks down lactose from dairy products, like cheese.

Symptoms of lactose intolerance often begin a few hours after eating dairy and can include:

  • Bloating
  • Diarrhea
  • Gas
  • Nausea
  • Abdominal pain
  • Stomach growling or rumbling
  • Vomiting
‌If you experience abdominal pain after eating pizza and other dairy products, you can avoid symptoms by limiting or avoiding dairy. You can also try over-the-counter lactase pills or powders, which could help you better digest lactose.

Certain pizza toppings are also gas-inducing, including onions and high-fiber vegetables, like artichokes or kale.

2. You’re Sensitive to Gluten

If pizza gives you diarrhea but other products that include dairy don’t, lactose might not be to blame. Instead, you might have a gluten sensitivity.

Gluten is a protein found in certain grains like wheat, barley, and rye as well as the flour in pizza dough.

 If your body can’t digest it properly, it can lead to abdominal cramps and diarrhea.
Celiac disease is an autoimmune disease and a more serious gluten condition. In celiac disease, eating gluten can permanently damage the small intestine and make it hard for the body to absorb nutrients properly.

Both conditions can cause similar symptoms, including:

  • Abdominal pain
  • Bloating
  • Gas
  • Diarrhea
  • Constipation
  • Nausea or vomiting
  • Fatigue
  • Headache
  • Skin rash
  • Anemia

If gluten-containing products like pizza are giving you stomach symptoms, talk to your doctor to determine the underlying cause. Celiac disease can lead to lasting damage to your digestive tract, so it’s important to cut out gluten if you’re diagnosed with the condition.

Since there are potential health pitfalls to a gluten-free diet, it’s best to check with your healthcare provider before making any dietary adjustments.

3. You Have a Food Allergy

Another reason pizza can upset your stomach is that you have a food allergy.

If you’re allergic to one or more pizza ingredients, eating them could cause mild to severe symptoms within minutes or hours.

Milk, wheat, and eggs are a few ingredients found in pizza that can cause allergic reactions in some people. Symptoms of a food allergy can include:

  • Diarrhea
  • Itchy skin, eczema, hives, or redness around the mouth or eyes
  • Nausea or vomiting
  • Abdominal pain
  • Nasal congestion or a runny nose
  • Sneezing
  • Tingly or itchy mouth

An allergist can help determine the ingredient that’s causing the reaction so you can avoid it to prevent future allergic symptoms.

Expect the allergist to ask you many specific questions about what you ate and when your symptoms occurred and for how long. Consider keeping a food diary before the appointment so you have these details at your fingertips.

If you have trouble breathing, swollen airways, and a rapid pulse after eating an allergen, these are signs of anaphylactic shock. Anaphylactic shock is a life-threatening reaction that can be fatal if you don’t get emergency treatment right away.

4. You Have Acid Reflux

Acid reflux might also be why pizza hurts your stomach. Reflux occurs when acid from your stomach flows backward into your esophagus, causing symptoms like:

  • Heartburn
  • Regurgitation
  • Trouble swallowing
  • Chest pain
  • A feeling of a lump in your throat

Certain foods can trigger acid reflux, including common pizza ingredients like fatty meats, tomatoes, and alliums, such as garlic and onions.

If acid reflux is the culprit, limit or avoid the ingredients that trigger your symptoms, or take antacids to ease your discomfort.

If reflux is a regular problem, your doctor can determine if you have gastrointestinal reflux disease (GERD), the chronic form of the condition, and whether prescription medication could help.

5. You Have Food Poisoning

You can get food poisoning from pizza if it contains ingredients that are raw, undercooked, or spoiled.

Meat and fresh fruits and vegetables are often to blame. Even a fully cooked pie can be contaminated if it touches a surface that came into contact with undercooked meat or other contaminated food.

Diarrhea and vomiting are a couple symptoms of food poisoning. Other potential symptoms include:

  • Upset stomach
  • Abdominal cramping
  • Blood in the stool
  • Fever
  • Headache

How to manage food poisoning depends on factors like the severity of your symptoms and the type of contaminant that caused your illness. Tell your doctor about your symptoms to determine the best treatment.

In general, though, if you get symptoms like vomiting or diarrhea after eating pizza, stay well hydrated with water and electrolyte-rich fluids, such as Pedialyte and Gatorade, to prevent dehydration.

The Takeaway

  • Eating pizza can cause gastrointestinal symptoms in some people for various reasons. Symptoms can include abdominal pain, diarrhea, and vomiting.
  • Lactose intolerance, a sensitivity to gluten, or food poisoning are among the potential causes of symptoms.
  • If you routinely experience symptoms after eating pizza, talk to your doctor to help narrow down the potential reasons for your reaction.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Symptoms and Causes of Lactose Intolerance. National Institute of Diabetes and Digestive and Kidney Diseases. February 2018.
  2. Gas and Gas Pain: Symptoms and Causes. Cleveland Clinic. February 23, 2024.
  3. Gluten Intolerance: Symptoms and Treatment. Cleveland Clinic. June 30, 2021.
  4. Definition and Facts for Celiac Disease. National Institute of Digestive and Diabetes and Kidney Diseases. October 2020.
  5. Food Allergy. Mayo Clinic. August 24, 2024.
  6. Food Allergy. American College of Allergy, Asthma & Immunology. June 28, 2023.
  7. Gastroesophageal Reflux Disease (GERD). Mayo Clinic. April 23, 2025.
  8. Food Poisoning. Mayo Clinic. February 23, 2024.
Meet Our Experts
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Julie Cunningham, MPH, RDN, LDN, CDCES

Medical Reviewer

Julie Cunningham has been a registered dietitian for more than 25 years. She is a certified diabetes care and education specialist (CDCES) and an international board-certified lactation consultant. She has served as the president of the Foothills Chapter of the North Carolina Dietetics Association (NCDA) and has been a member of the executive board of the NCDA.

Ms. Cunningham received a bachelor's degree from Appalachian State University in North Carolina. She subsequently completed a master's degree in public health nutrition at the University of North Carolina at Chapel Hill.

Ms. Cunningham has worked in women's and children's health, cardiology, and diabetes. She is the author of 30 Days to Tame Type 2 Diabetes, and she has also written for Abbott Nutrition News, Edgepark Medical Health Insights, diaTribe, Babylist, and others.

A resident of beautiful western North Carolina, Cunningham is an avid reader who enjoys yoga, travel, and all things chocolate.

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Kathleen Ferraro

Author
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