Yes, onion is low histamine. Beyond that, onions are part of the allium family, a group of vegetables which have a characteristically pungent odor and flavor, such as that in garlic, leeks, shallots, and onions. This scent has health benefits, as well, believed to range from being antimicrobial and antioxidant to even “boosting” the immune system. The smell comes from the presence of organosulfur compounds that are present to varying degrees in all alliums. Each one of these is low histamine and can be used to flavor bland dishes. Unless you’re eating low FODMAP (you’ll know if you are) or have a sulfate sensitivity, you can add onions to your diet even in early stages of the elimination diet.