With the improvement of living standard and the change of diet structure, the incidence of colon cancer is on the rise year by year. And about sixty percent of the clinically diagnosed colon cancer patients had suffered from colitis. For this reason, what are the causes of ulcerative colitis? What are the symptoms of ulcerative colitis? and how to treat ulcerative colitis effectively? About sixty percent of the clinically diagnosed colon cancer patients had suffered from colitis. Among the five hundred and ninety-eight cases of colonoscopy, ninety-three percent had various problems, including four cases of colon cancer and thirteen percent of precancerous lesions such as atypical hyperplasia and tubular adenoma. Among the 20,000 people who had frequent diarrhea medical examinations, more than 95% of them treated diarrhea caused by colitis as general diarrhea and took some medicine casually to stop the diarrhea and then stopped treating it, and another 3% did not pay attention to it after being diagnosed. Diarrhea is a common symptom of gastrointestinal diseases. It is due to the dysfunction of secretion, digestion and absorption and movement of the gastrointestinal tract, resulting in thin stools and increased frequency, and those who have been ill for more than 2 months are called chronic diarrhea. Clinically, it is divided into: diarrhea caused by gastric diseases and regurgitation of intestinal contents or bile into the stomach; diarrhea caused by various inflammatory diseases of the intestinal tract such as bacillary dysentery, ulcerative colitis, clonal disease, incomplete intestinal obstruction, tumors, dyspepsia, dysbiosis, allergy to fish and shrimp, food poisoning and certain diarrheal drugs and antihypertensive drugs; diarrhea caused by endocrine disorders such as hyperthyroidism and hypoadrenocorticism; functional diarrhea. such as emotional diarrhea, irritable bowel syndrome. Among the above causes of diarrhea, the most common are various intestinal infections, colon and rectal cancer, food poisoning caused by staphylococcal enterotoxins, and irritable bowel syndrome. There is a quantitative to qualitative process from diarrheal colitis to colon cancer, and patients with colitis have a risk of colon cancer of up to 40%. Therefore, it is possible to avoid colon cancer only if colitis is completely cured. Colon cancer has the highest incidence in the age group of 40 to 60 years old, and it is recommended that regular colonoscopy should be done from the age of 36 years old, especially for those who suffer from colitis and frequent diarrhea. Since colon cancer develops slowly, early symptoms can be detected by colonoscopy and can be cured without surgery.