Irritable Bowel Syndrome (IBS) symptoms can be triggered by a variety of factors including for example diet, life situation (stress), and hormones.
Diet
There is a difference between food allergy or food intolerance and IBS. Even if both IBS and food intolerance/allergy can result in the same kind of symptoms including pain, bloating, and diarrhea, IBS is not caused by a food allergy/intolerance. Still many people with IBS experience that certain food or beverages worsen their symptoms. Examples of such food are dairy products, beans, citrus fruit, wheat, and cabbage.
Life situation
IBS is not caused by a certain life situation but it seems as if there is a strong relationship between for example IBS symptoms and increased stress. Also, other factors such as activity level, exercise, and different habits can influence IBS symptoms.
Hormones
We don’t know what causes IBS but we know that women are more likely to have IBS than men. It is also known that symptoms are wearing during or around menstrual periods. Note that other conditions like endometriosis can have some symptoms similar to IBS. It is always important to get a correct diagnoses.