In anatomy, a polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated; if it is attached without a stalk, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, ear, sinus(es), urinary bladder, and uterus. They may also occur elsewhere in the body where there are mucous membranes, including the cervix, vocal folds, and small intestine. Some polyps are tumors (neoplasms) and others are non-neoplastic, for example hyperplastic or dysplastic, which are benign. The neoplastic ones are usually benign, although some can be pre-malignant, or concurrent with a malignancy. The name is of ancient origin, in use in English from about 1400 for a nasal polyp, from Latin polypus through Greek. The animal of similar appearance called polyp is attested from 1742, although the word was earlier used for an octopus. Digestive polyps
Relative incidences by location:

Colorectal polyp
While colon polyps are not commonly associated with symptoms, occasionally they may cause rectal bleeding, and on rare occasions pain, diarrhea or constipation. They are a concern because of the potential for colon cancer being present microscopically, and the risk of benign colon polyps becoming malignant over time. Since most polyps are asymptomatic, they are usually discovered at the time of colon cancer screening.
It is believed that some changes in the diet might be helpful in preventing polyps from occurring, but there is no other way to prevent the polyps from developing into cancerous growths than detecting and removing them.Colon polyps as they grow can sometimes cause bleeding within the intestine, which can be detected by an occult blood test. According to American Cancer Society guidelines, people over 50 should have an annual  occult blood test. People in their 50s are recommended to have flexible sigmoidoscopies performed once every 3 to 5 years to detect any abnormal growth which could be an adenomatous polyp. If adenomatous polyps are detected during this procedure, a colonoscopy is recommended. Medical societies recommend colonoscopies every ten years starting at age 50 as a necessary screening practice for colon cancer. The screening provides an accurate image of the intestine and also allows the removal of the polyp, if found. Once an adenomatous polyp is identified during colonoscopy, there are several methods of removal, including using a snare or a heating device. Colonoscopies are preferred over sigmoidoscopies because they allow the examination of the entire colon and can detect polyps in the upper colon, where more than half of polyps occur.It has been statistically demonstrated that screening programs are effective in reducing the number of deaths caused by colon cancer due to adenomatous polyps. The risk of complications associated with colonoscopies is approximately 0.35 percent, compared to a lifetime risk of developing colon cancer of around 6 percent.