[surferjoe2007]

I better say something since this seems to be catching on. The methyl salicylate in icy hot can be fatal with excessive applications. It has happened with an athlete who made constant use of muscle rub, though more often it happens in small children.

http://en.wikipedia.org/wiki/Methyl_Salicylate#Safety_and_toxicity

Tiger balm is less dangerous, but still harmful if severely overused.

Less frequent use should be totally fine AFAIK.