Indications for use are expending daily:

Overactive bladder, diabetic nerve pain, excessive sweating, migraine headaches, voice tremors — these are just a few of the conditions that the drug Botox can treat.

This week came the news that yet another condition might be alleviated by Botox — benign prostatic hypertrophy, or prostate enlargement.

Botox's manufacturer, Allergan, says that it is one of the most used medications worldwide, approved for 20 problems in more than 75 nations. This list will likely grow as new discoveries are made.

How did one drug — which was originally approved to treat excessive blinking back in 1989 — become so useful? The answer lies in how Botox can be injected directly to the source of the problem — usually an overactive muscle, gland or nerve connection — with few lingering side effects, making it easy for scientists to experiment with it on different problems.

"Every group of physicians that have taken on botulism A have found innovative uses for it," said Dr. Alastair Carruthers, a clinical professor of dermatology at the University of British Columbia. Carruthers is also half of the husband-and-wife team that first reported Botox's cosmetic use in the 1990s.