as far as I understand, the yellow toenail is usually due to an overgrowth of microforms like candida or other yeast. I found some really good information on balancing the body to prevent and reverse such problems in a book by Dr. Robert O. Young, called the pH miracle. There is also a site for his supliments, I mostly recomend the pH drops and super greens, just cause they are what I have tried so far and had great success with (more energy, especially in the morning, wake up after 7 hours sleep with out alarm, eczema fading fast, and less recovery after exercise). But that's just my experience, check it out for yourself. The web site I recomend for the product is http://innerlightinc.iact1.com/mikelarsen . Or you can contact me directly, and I can help you out. Good health to everyone, Mike