What’s the worst reaction you ever have had consuming food, vaccine, medicine and or a drug?

The antidepressant the doctor put me on had me in a fit of giggles all the time. Made me sleep 16 hours a day. Plus I couldn’t ejaculate so after a month I had a boner that wouldn’t go down. (Not good for someone working in palliative care) and quitting cold turkey made me feel like I had Shingles.