It's
fungus that grows on your
toenails. Actually, not just
on them but
under and really
through them. You know you've got it when your toenails are all
thick and
yellow and
break easily. If you let them get too long they
hurt a bit.
Once you get it, it's a pain to get rid of. There are now prescription medicines that do the trick, but they have side effects--and in fact, someone died in the clinical trials for one of them. You know what, toenail fungus stinks, but it ain't worth my life. Oh, and the drugs screw up your liver.
I have had success with applicationsof tea tree oil--I was able to reclaim one nail from the fungus by twice daily applications. I am now using a compound by Uncle Harry's Natural Products that consists of essential oils of thyme, oregano, neem, and cinnamon. Much the same antimicrobial effect, it was a bit cheaper. There are other products on the market for topical application that all say they work but are probably dependent on diligent application of them--I sometimes lapse for weeks at a time.
The other thing I find useful is to cut your nails extremely short. This is more comfortable and probably lets the topical preparations penetrate better.
I suppose, as well, good foot health would help too--wearing socks when wearing shoes, cleaning your feet and keeping them dry.
Toe fungus is not immediately contagious (my wife has not gotten it) but has to come from somewhere. It may be related to athlete's foot for all I care.