Onions and IBS go hand in hand as onions are a high fodmap and a common trigger food for symptoms of IBS and SIBO such as: Gas Abdominal pain and diarrhea bloating When someone has irritable bowel syndrome or digestive issues, one of the questions I always ask is, how do you tolerate high fodmap foods such as onion and garlic? Most people with IBS and SIBO notice a worsening of IBS symptoms after eating onions or garlic, even in small amounts. ~ Didem