Anything with MSG (monosodium glutamate) which means anything with regular chicken broth, ranch dressings, seasoned chips, a lot of frozen or prepared dinners. I'll have a headache, nausea, heart palpatations, sweating, etc. starting about 4-6 hours after I eat it and it can last for up to 12 hours. Yet doctors don't consider that an allergic reaction - they call it a "physical reaction" - go figure.