There's a whole forum on it at this site, and it would be a good idea to read it as I'm only able to give you a brief rundown on Candida. Fellow members, please correct me if I'm wrong on this:
Candida is naturally occuring in the bowels, but your natural balance of bacteria keeps it in check. When you take Antibiotics , or induldge in the Standard American Diet of too many refined foods, the balance can be tipped and the Candida will grow out of control. Hannah Kroeger had said that it can manifest anywhere in the body, not just as Thrush or a Yeast infection. In fact, I do believe she said that if you were to treat the members of the mental ward for Candida, most of them would go home as candida manifest in the brain can cause Depression and psychotic behavior.
One of the first things you do when you try to rid yourself of Candida is to modify the diet by removing what Candida likes to live on. Sugars and Yeasts are removed, so the maple syrup in The Master Cleanse could pose a problem for those already suffering from Candida.
A simple sign of someone suffering from Candida are those who are always craving sweets. I found that after I got mine under control, candy was really not attractive to me anymore while during the time that I had candida (years?) I ate lots of chocolate and ice cream.