Colic six months after rectal surgery is usually not directly related to the surgery, but may be due to gastrointestinal spasm, intestinal obstruction or intestinal tumors. 1. Gastrointestinal spasm: Gastrointestinal spasm is usually paroxysmal, which is caused by the spasm of gastrointestinal system, and it will cause the patient’s abdomen to have strong colic symptoms, which can last for a few minutes and sometimes can last for more than 10 minutes. 2. Intestinal obstruction: Intestinal obstruction can also cause the symptoms of abdominal cramps, and some patients also have constipation and vomiting. 3. Intestinal tumors: Intestinal tumors in the middle and late stages can also cause severe abdominal cramps, which is mainly due to the invasion of tumor cells into the intestinal tract, resulting in intestinal compression, which results in pain. Colicky stomach after six months of rectal surgery may also be caused by stomach tumor, kidney stones and other diseases, which should be checked by doctor in time.