How to tell if your bowel is clean for colonoscopy

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

Whereas previous studies suggest that patients’ assessments of bowel preparation are not reliable, a study suggests that photographic examples of rectal effluents may help predict the quality of bowel preparation.

A clear yellow rectal effluent (diluted urine) is the goal. The yellow color is from bile stain.

No two persons are the same. Diseases, medications and differences in bodily functions affect bowel preparation. It takes different times for different individuals to achieve a clear yellow rectal effluent.

Different Poop Stages during Bowel Preparation

  1. Solid stool: This may be the first poop you have after taking the bowel cleansing agent.
  2. Semi-solid stool: This may be the first poop in some patients.
  3. Watery stool: This is very common in the early phase of purging the bowel.
  4. Liquid with small amount of feces: This is the mid-phase of bowel cleansing.
  5. Yellow liquid with particulate materials: This is the late phase of bowel cleansing.
  6. Turbid yellow liquid without particulates: This means you are near ready.
  7. Clear yellow liquid: This means you are ready. If you have not finished your bowel cleansing agent, you should still finish it as instructed. The intestine continues to produce fecal material so rinse out the colon with the remaining bowel cleansing agent.