Colorectal cancer can be prevented, on the one hand because most colorectal cancers develop from polyps, and on the other hand because most early cancers can be completely cured. Therefore, the main way to prevent colorectal cancer is to detect colorectal polyp lesions, or to detect early colorectal cancer lesions. There are various types of colorectal polyps, and only some of them develop into colorectal cancer, and even then this is a long process, thus giving us plenty of time to intervene. However, clinically, colorectal polyps are asymptomatic. Many patients have already turned into colorectal cancer by the time they develop symptoms. Therefore, we are required to perform a physical examination to detect these colorectal polyps when they are asymptomatic. Those who are over 35, especially those with gastrointestinal cancer in their family line, are encouraged to have a colonoscopy. If polyps are found, they can be removed very simply under endoscopy and can be completely cured without surgery or chemotherapy. And it is important to have the polyps evaluated by an experienced physician to determine the chance of such polyps becoming cancerous or to determine the timing of follow-up review. There is no need to panic when early stage cancer appears, as most early stage cancers are curable at this time, but require treatment or post-operative guidance from an experienced physician. There is no definitive conclusion on what diet or medications can prevent colorectal cancer. Since many colorectal cancers develop slowly from colorectal polyps, colonoscopy can prevent the development of colorectal cancer by finding colorectal polyps and removing them endoscopically. Simple endoscopic excision of colon polyps before they become cancerous can prevent the occurrence of colorectal cancer. Point: Even if there are polyp lesions in the intestine before the occurrence of colorectal cancer, there may not be symptoms clinically, so people over 40 years old should have a colonoscopy to detect possible precancerous lesions. People who have a family history of cancer, especially those who have gastrointestinal cancer in their family members and their blood relatives should have a colonoscopy. People with chronic abdominal pain, mucus stool, blood in stool, positive fecal occult blood, or those who think they have hemorrhoids should also undergo a colonoscopy, which is very simple as polyps can be removed within 20 minutes. After removal, you can stay in the hospital for a few days until the wound grows back and you can be discharged.