Dr. Mark Hyman, MD, and Dr. Todd LePine, MD, discuss histamine intolerance. Histamine is released by mast cells, a type of white blood cell, and works as a neurotransmitter. Too much or too little of this chemical can cause problems. Numerous conditions have histamine issues at their root, such as migraines, brain fog, food sensitives and allergies, edema, and more. The doctors talk about diet and lifestyle changes that can help ameliorate histamine intolerance permanently.