What is the strongest allergy medication out there?

What is going on? If you are having severe allergic reaction (food, bees, medication), call 911 now. Take your epinephrine as prescribed for allergic shock (anaphylaxis). For non-urgent matters, diphenhydramine is plenty strong for most mild allergies (and can cause drowsiness - don't drive). Many less strong antihistamines are over the counter. If not work - time to make an appointment with the provider.