Capsaicin, pepper’s active ingredient, is literally caustic to the flesh. But somehow, human taste has evolved to enjoy the taste of pepper. Why? Because capsaicin is a natural disinfectant, and it kills many types of food-borne bacteria. Put hot pepper in slightly rancid meat, and it inhibits bacteria. The person who eats the meal with the pepper lives. The person who eats the meal without the pepper gets sick and could die.
