DEAR DR. ROACH: I am a 76-year-old male who is in relatively good health. For the past six months, I have been experiencing diarrhea on and off. I initially spoke to my general physician, and he thought it could be lactose intolerance. I reduced my dairy intake, drank lactose-free milk, and took Lactaid pills before eating dairy.

Clostridioides difficile is an uncommon but quite serious cause of diarrhea, and it is often associated with antibiotics.