Colorectal melanosis is unfamiliar to the vast majority of medical practitioners and patients. The traditional view is that this disease is a benign reversible disease and its incidence is extremely low. In recent years, its incidence has increased significantly, which may be related to the popular use of fiberoptic colonoscopy and the increased awareness of this disease. Some literature reports that colorectal melanosis is a risk factor for colorectal cancer, so it is gradually attracting people’s attention. Through fiberoptic colonoscopy, we can see that the colonic mucosa of patients resembles tiger leopard skin-like pigmented plaques or betel nut slice-like plaques, and gray-white or gray-black mucosa can be seen between the pigmented plaques. It is believed that the causes of the disease are mainly focused on two points: first, the disorder of intestinal function, mainly chronic constipation; second, the long-term use of anthraquinone-based laxatives, such as rhamnolipid, diarrhea leaf, aloe vera and rhubarb. In fact, these two factors are also complementary, because chronic constipation and laxatives are themselves closely related, so the relationship between long-term abuse of anthraquinone laxatives and colorectal melanosis is recognized by most people. Colonoscopy and biopsy have revealed that the severity of colonic melanosis is closely related to the use of laxatives, and that colonic melanosis is reduced or disappears when laxatives are discontinued. Perhaps this is the reason why many medical practitioners are indifferent to it, or even ignore it. However, with the development of science, we found that the incidence of colorectal cancer and polyps in colorectal melanosis is higher than that of other people, especially the incidence of adenomatous polyps, which is now recognized as a precancerous lesion. The facts suggest that there may be some intrinsic relationship between colorectal melanosis and the occurrence of tumor, whether it is concomitant or causal needs to be further explored. Therefore, when colonoscopy reveals colorectal melanosis, the presence of colorectal cancer and adenomatous polyps should be alerted. For patients who have been diagnosed with colorectal melanosis, regular colonoscopy is essential. Although there is a potential for increased incidence of colorectal neoplasia, there is no evidence that colorectal melanosis can cause direct damage to the body, so its treatment is generally non-surgical. The prevention of laxative abuse is the fundamental method of preventing and treating colorectal melanosis, and there is no prescription for patients with colorectal melanosis without a history of laxative use.