What was your scariest allergic reaction?

The scariest allergic reaction I ever had was when I accidentally ate a peach. I had no idea that peaches were one of the fruits that I was allergic to, and within minutes of eating it, my throat started swelling up and getting tight. I started feeling lightheaded and short of breath, and if I hadn't gone to the hospital right away, it's possible that things could have ended up much worse.