Can chronic diarrhoea be inherited?

Love the title of your post. I was picturing someone sitting at the reading of the will of some long lost elderly relative, and finding out the total sum of their inheritance was a sack full of home produced diarrhoea, straight from the deceased’s arse.

See a gastroenterologist. Could be IBS or something else.

Diarrhoea is a symptom, not a disease.

Others have mentioned how there are medical conditions whose symptoms can include diarrhoea that seem to be linked to inherited genes.

Irritable Bowel Syndrome and Crohn's disease are both known to be more common amongst those who have relatives with the conditions. But of course it is also possible that you have some other problem that's completely different to whatever it is that's causing your grandmother's problem.

You shouldn't be seeking advice about this problem here or on any other social media website. You really should see a doctor about this. Chronic diarrhoea can be a symptom of serious issues, and the fact that food is not being properly absorbed in your bowel can result in medium- and long-term health problems in addition to whatever is causing the diarrhoea.

It's less "chronic diarrhea" that can be inherited and more so various medical conditions that cause that symptom. In addition to this, diets tend to be passed down accidentally as well. (If your parents eat healthier, you'll be more likely to as well.)

You need to see a doctor.

I am aware of at least 1 medical condition that may lead to increased diarrhea that is often passed down genetically.

However, there is no diarrhea if you eat the proper diet, except for the occasional diarrhea people get from bad food or other illnesses.

You need to start looking at what you are eating and what possible medical conditions make a person more susceptible to diarrhea; and the recommended diets for those people.