Hello! Thank you for the query. He advised colonoscopy because presence of one source of bleeding (hemorrhoids) does not rule out other possible reason (inflammatory bowels disease at your age). Diseases can coexist and give same symptoms. However at your age, if there is no other symptoms than fresh bright blood on the stool, other than hemorrhoids diseases are unlikely. If no weight lost, no constipation, diarrhea, mucus in stool, hemoglobin level is fine, no abdominal pains, colonoscopy seems controversial. You may try some treatment and see if this will help with bleeding. Hemorrhoids suppositories, sitz baths with Quercus Cortex, avoiding constipations (fiber rich products, mineral water intake), increased physical activity should help if you are facing only hemorrhoids. If no improvement, than colonoscopy is necessary indeed. Hope this will help. Regards.