What gives horseradish its bite, and how do you like to eat yours?

It's hot, and tangy, clears out the sinuses. Can anyone tell me what it is in horseradish that attacks the sinuses so? Are there any ways to get that delicious flavor and warmth without suffering pain? Gives me a runny nose and heartburn if I eat too much, so we can't keep it in the house or I'll eat it with every meal! I'll put my horseradish on just about any kind of meat. A favorite snack of mine is a cheese stick with cream cheese and horseradish, wrapped in roast turkey.