Tummy cramps refer to smooth muscle spasms of the stomach and intestines, causing gastrointestinal cramps for a number of reasons, to list the more common causes: 1, dietary reasons, is one of the most common causes of gastrointestinal cramps. For example, eating spicy food, eating cold or eating greasy, poorly digested food, etc., may cause the mucosal reaction of the gastrointestinal tract, and cause muscle spasm. 2, gastrointestinal tract lesions, gastrointestinal tract mucosal erosion, ulcers, polyps, etc., causing gastrointestinal tract malfunction, may cause gastrointestinal spasm, especially under the stimulation of food is more likely to produce. 3, if the person may also appear when angry.