I'm having diarrhea and can't eat diary food.what food is suitable when having diarrhea?

Depends on: If this diarrhea is new or chronic. If chronic you need to determine why you are having diarrhea. If it just started avoid foods that are high in fats and proteins as they tend to be more difficult to digest, which is why the BRAT(bananas rice apples sauce toast) is often recommended. This diet can be short of many nutrients so don't use it long term and make sure you are getting salt replacement