Left small abdominal cramps are professionally known as left lower spasmodic pain, caused by the following causes: 1, left small intestine dysfunction: normal human small intestine will have rhythmic contraction 3-5 times per minute, when intestinal dysfunction is caused by plant nerve dysfunction, small intestine contraction is out of rhythm spasmodic contraction, up to 7-8 times per minute, or even 10 times rapid contraction. When the rapid contraction will cause intestinal spasm, manifested as paroxysmal spasmodic pain, at this time can be given drug treatment for intestinal dysfunction; 2, small intestine lesions: if there is cramping, usually persistent cramping, at this time should consider whether there is a lesion or intestinal obstruction of the small intestine. If rectal cancer or sigmoid colon cancer causes intestinal obstruction, there will be paroxysmal pain and abdominal distension, so you should seek medical treatment in time.