Why do i get bad stomach aches & mild diarrhea the day after i eat peppers & spicy food? i'm not allergic

Sensitive stomach: Tolerance to foods differs from person to person and depending on the amount eaten. Some of us may be sensitive to peppers and spicy foods. If that is the case, both stomach and intestines may respond by going into a spasm which may result in a bad stomach ache and mild diarrhea. Avoiding pepper and spicy food or limiting their intake may be helpful.