A colonoscopy lets a doctor see inside the large intestine. It helps find problems early or figure out why someone feels sick.
The doctor uses a thin, flexible tube with a tiny camera. The camera sends clear pictures that can be saved. The doctor can also remove small growths or take tiny samples for testing.
Doctors suggest a colonoscopy if they suspect colon disease, like cancer, or if a person has rectal bleeding, hidden blood in stool, changes in bathroom habits, long‑lasting diarrhea, constipation, or trouble passing stool.