If you eat too much lettuce, you will not get cancer. On the contrary, eating more lettuce can reduce the occurrence of cancer, especially colorectal cancer. Lettuce is rich in vitamin C and dietary fiber. Eating more lettuce can promote the excretion of fat in the intestine, and reduce the time of toxins in the intestine and the stimulation of intestinal contents, so it can reduce the chance of colorectal cancer. The pesticides contained in some lettuce can exceed the standard and may cause poisoning if not cleaned, and the pesticides contain many carcinogenic substances, which may cause cancer after absorption into the body. So before eating lettuce must be cleaned of pesticides on the lettuce.