Colonoscopy's normal, but there's a groove in the stool.

Colonoscopy normal stool groove has nothing to do with it, it is likely to be hemorrhoids or anal canal disease, because stool will stay in the rectum, when passing through the anus will be squeezed by the anus, there are hemorrhoids or anal stenosis, will form grooves, so there is no special relationship. Usually diet should eat light good digestion of food, do not overeat, do not eat spicy food, do not eat smoked pickled food, do not eat smoked fried food, to maintain a happy mood, to exercise properly, when necessary, can give some intestinal probiotics treatment common Bacillus licheniformis, Bifidobacterium aurum and so on.