My son has had irritable bowel syndrom and he also caught a parasite from the drinking water when he went to France. He has alot of food allergies, When you have food allergies you can have diareha and cramping all the time if your eating those food's on a regular basis. Has he seen am allergist? My son had to keep a long of everything he ate from day to day, if he had a bad day he could look back and try to figure out what was different that he ate that day that made him sick.We would circle it and totally omit that food. He was not to eat fried, greasy or acidy food (no tomatoes,oranges or spicy foods). He has 33 food allergies, he cannot have cows milk, there are times when he will have pizza or Ice cream because he loves it, but he suffers later. Then I say to him was it worth it, my son is 21 years old, he has had bowel problems and cramping since birth. If he stay's away from the foods that make him sick he is better. I think your fiance need to have allergie test's done, it will make his life alot more tollerent and he'll feel better to. I wish him luck.