Pizza can sometimes cause diarrhea in some people. Here are some possible reasons why this may occur:

1. Food intolerance or allergy: Some people may have a food intolerance or allergy to ingredients found in pizza, such as wheat, cheese, or meat. This can cause symptoms like diarrhea, stomach cramps, and bloating.
2. Spices or additives: Pizza may contain spices or other additives that can cause digestive problems in some people. For example, some people may be sensitive to preservatives or other chemicals found in pizza, which can cause diarrhea or other gastrointestinal symptoms.
3. Lactose intolerance: Some people are unable to digest lactose, a sugar found in milk and dairy products. If a person has lactose intolerance and eats pizza that contains cheese, they may experience diarrhea or other digestive symptoms.
4. Other medical conditions: There are many other medical conditions that can cause diarrhea, including inflammatory bowel disease (IBD), celiac disease, and infections. If a person is experiencing diarrhea after eating pizza and they have other symptoms or have a history of medical problems, it is important to consult with a healthcare provider to determine the cause of their symptoms.

In conclusion, pizza can cause diarrhea in some people due to food intolerance or allergy, spices or additives, lactose intolerance, or other medical conditions. If you are experiencing diarrhea after eating pizza and you are concerned, it is important to pay attention to your symptoms and to consult with a healthcare provider if you are concerned.