Your last rectal effluent (stool after finishing your bowel prep agent) can act as a guide. Your stool should be clear, yellow, light and liquid. The presence of dark particles or thick brown or black stool means you are not ready for colonoscopy. If your stool is not clear after taking your entire bowel prep agent, you may need additional prep agent.

Stool ColorDescriptionReadiness
Dark, thick, particlesNOT READY
Brown, thick, particlesNOT READY
Dark orange, semi- clearNOT READY
Light orange, mostly clearALMOST READY
Yellow, light, clearREADY