Tyramine is a biogenic amine. Its similar in some ways to histamine, except broken down by MAO not DAO . Biogenic amines tend to be produced by protein as it ages (breakdown product of protein along with other amines) and sometimes by bacterial processing of undigested stuff. I should have clarified that the poll is only useful if NOT on an MAO-A inhibitor. That is, those who are on a drug known to inhbit the monamine oxidase A enzyme, are known to have bad effects from tyramine containing foods, but am asking about those who are not on such meds. Am asking because its a missing puzzle piece for me. ONe of the odd things that happened to me when I crashed from this illness was a senstivity to tyramine foods that has grown over the years. I think its connected, but really am not sure how.