Familial adenomatous polyposis is an autosomal dominant disorder that presents with adenomas of varying sizes throughout the colorectum. Most polyps appear around the age of 15, and the number of polyps is small at the beginning and increases with age. Symptoms such as abdominal discomfort, abdominal pain, blood or mucus in the stool, and increased frequency of stools may occur. If familial adenomatous polyposis is not treated in time, it will eventually become cancerous. Early detection, diagnosis and treatment are recommended, and adolescents with a family history of the disease should go to the hospital for colonoscopy during their teenage years.