What emergency items must be in my medicine cabinet?

Depends: Fever or pain meds, ammonia for stings, bandages, thermometer, something for sunburn depending on time of year and location tourniquet or rubber bands to stop bleeding, Benadryl (diphenhydramine) , tape , gauze.

It depends: It depends on how adventurous you are. At a minimum i'd say an assortment of bandages, ace wrap, bendable splint, anti-itch cream, scissors, fine tweezers, benadryl, (diphenhydramine) tape, burn spray, ibuprofen, antiseptic wipes. If you're a camper or hiker, you might look into a kit from adventure medical kits.