Thanks for posting your query at DoctorSpring.com. I am Dr.Ratnakar Kini and I am pleased to assist you.
Though certain food items can make the stool look green, a faster transit time of the bowel also can cause greenish stools. In this case, it is the bile that makes the stool look green. Normally the bile gets absorbed in the last part of the small intestine. But when the bowel works in a hurry, not all bile gets absorbed leading to greenish stool.
Make sure you are not on any medication that causes the bowel to work faster. Sometimes it occurs due to infection.
So if it persists, i would recommend getting a stool test done.
Hope I have answered all your queries, Please feel free to discuss further.