A pill camera is a capsule-sized device used in endoscopy to record images of the digestive tract. It contains a tiny camera that takes pictures after being swallowed. The primary use is to examine the small intestine, which other endoscopy methods cannot access well. The capsule transmits images wirelessly to an external receiver as it passes through the tract. Images are then reviewed by doctors to diagnose problems, though the capsule cannot treat any issues found. While generally safe, there is a small risk of the capsule being retained in the body for an extended time. It works using electromagnetic waves and has protections to safely pass through the digestive system.