It is pretty normal for stool colour to change from dark yellow to brown or green. The actual colour is reflective of the type and the quantity of food we consumed and it is affected by the bile juice found in our digestive system. Green stools, in general, does not suggest any major problem.
Bile juice, being yellowish-brown in colour, is responsible for our stool colour most times. Any change in the bile secretion due to various reasons can affect our stool colour significantly. Green leafy vegetables in large amount or vitamins rich in iron, on the other hand, can turned our stool dark green.
The stool colour which we should be concern about is black or maroon stools for no apparent reason. This suggest possible bleeding from the gastrointestinal tract and you should seek medical help immediately.
- Dr Quan