When you have a bologna sandwich, what do you put on it? How about on a hot dog or a hamburger? If you lived 200 years ago, you probably would have said mustard, mustard, mustard!
You may dislike it if you find the taste of mustard too zippy, but people throughout history might disagree with your opinion. Long before ketchup was ever thought of, mustard was in common use. It was appreciated not only for its taste but also for its medicinal qualities.
Mustard seed has a long history of use in the East and Middle East. The hot feeling you get from mustard in your mouth has the same action on the skin. It increases the circulation of blood wherever it is applied as a plaster. Do you remember the rhyme about Jack and Jill? The second verse tells of Jack putting a mustard plaster on his injured head. Even now, some people use it to get rid of a chest cold faster.