I would say to Google search Celiac disease. It is essentially a very bad allergic reaction to anything containing Gluten, which can be found in wheat, rye, barley and most oats. It is in many many everyday products. It can cause numerous reactions in your body, including IBS (irritable bowel syndrome) diarrhea, cramps, mouth sores, weakened immune system etc...
Actually Celiac is NOT an allergic reaction to anything. It is an intolerance of the gluten in wheat, oats, rye and barley. It damages the villi which are located in the small bowel, this is where nutrients are absorbed and why many Celiacs are deficient in vitamins and nutrients. When a Celiac adheres to a strict gluten free diet the villi will repair themselves and the body will return to the way it should be. When gluten is consumed it can effect you in many different ways. The bonus is that with this condition no medication is required and the diet tends to a very healthy one.
Hope this helps
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