What is Travellers’ Diarrhea? Travellers’ diarrhea is the most common illness affecting international travellers. The symptom is so well known that it has earned many nicknames, including “Montezuma’s Revenge”, “Pharaoh’s Revenge,” and “Delhi Belly”. Recent studies show up to 70 percent of travellers will come down with diarrhea symptoms during their trip. Often, travellers’ diarrhea itself is not an illness. It is usually a symptom of infection like food poisoning or e. coli. The best way to avoid travellers’ diarrhea is