Lysterine. I swear it work. Soke your toes every time you get out of the shower. You will see results instantly.
Always keep your feet as dry as possible, as fungus LOVES dampness. I put a few drops TEA TREE OIL on my toenails and cuticles and rubbed it in thoroughly EVERY day.
Do this daily - even when you see healthy nails growing. Contiue until all of the thick yellow nail grows out completely... which will take several months. Also, do NOT polish your nails - it only seals in the fungus and makes it worse (and harder and longer to get rid of).
If your toenail gets really thick and yellow, it is a form of fungus.
Take a nail file and run it over the surface of the toenail. Rub it both horizontally and laterally to make uneven grooves in the top of the nail.
Then rub Vick's Vapor Rub into the top of the toenail. The grooves will help keep the Vick's on the toenail. Do this for several days/nights in a row as often as you can.
The Eucalyptus in the Vick's will kill the fungus on the nail faster than any store-bought anti-fungal available !