Black pepper is probably one of the most ubiquitous spices in the world, certainly in the United States. When was the last time you saw a salt shaker without its peppery twin? It hasn't been a hot topic for scientific research but there are many traditional medicinal uses for pepper
Piperine is an alkaloid in black pepper (the berry of a kind of evergreen plant) has been compared to the capsaicin in hot peppers (like jalapenos, chilis etc.). Both have anti-inflammatory properties and have been useful in arthritis for some people. It is completely counterintuitive to my mind, but the anti-inflammatory properties are supposed to help stomach ulcers too...though I can't imagine chowing down on pepper with an upset stomach.
In aromatherapy, black pepper oil is used to promote mental alertness. Ingesting it is supposed to help mental focus as well as the fragrance does. Sounds like as good of an excuse as any to throw some pepper on your morning eggs.
Taste-wise, this particular spice has a strong comfort-association for me. My Grandmother (a major influence and a heckuva good cook) was a whiz at using just the right amount of black pepper to give food flavor without blowing a little kid's head off. The best thing she made with black pepper was her hamburger gravy. I'm not talking about some fru-fru health food here. I'm talking about gut-filling, make a kid happy, old-fashioned, over-biscuits, I'm-hungry-as-a-newborn-vampire Southern gravy.
Although I wouldn't recommend a steady diet of hamburger gravy, with or without black pepper, this spice deserves its place at the table.