Joking on the job can have a positive effect on productivity and morale. A disease or ailment of any kind, however, is nothing to kid about in the workplace, whether you personally suffer from one or not. But some people are so socially inept that they can't help but make jokes that turn others around them into their punch line.

Such people need a minor intervention of sorts. I would let your co-worker know that joking about afflictions may make him look insensitive and unprofessional. Even worse, it might land him in hot water with the human-resources department or management, who would frown on humor that potentially creates a hostile environment. You should also remind him of something Laurence Sterne once wrote. "For every 10 jokes," said the 18th century novelist, "you acquire a hundred enemies."

In addition, you might present him with a joke book that contains more acceptable humor. One that comes to mind is the "Pretty Good Joke Book," by Garrison Keillor, which offers humor that should delight, not distress, anyone. Tell your jokester that you're offering this gift since you believe he'll need new source material from now on. With any luck, your talk and the book will help his humor change faster than you can say "A pig walked into a bar ... "