Spinach is a very common vegetable that everyone used to have especially in Salads. But Spinach allergy also exists. It is quite rare form of allergy which generally creates stomach cramps. If after eating spinach you always suffer with stomach cramps, then you may have a condition called histamine intolerance. Eating spinach also increases your dietary fiber, which could lead to temporary stomach cramping and other digestive symptoms. The high amount of salicylates present in this leafy, green vegetable can be held responsible for triggering off the allergic reactions. A specific antibody called immunoglobulin E is also created to combat the protein. Food scientists have also identified kDa, another protein present in the spinach as an allergen too.