It's for real. I had systemic Candidiasis and it was causing a multitude of health problems. My primary care physician (regular MD, but with an interest in holistic approaches) prescribed Nystatin and Diflucan. The Diflucan did for the major overt symptoms, but it took several YEARS to totally heal from it.
The probable cause was from taking too many antibiotics for too long because of sinus infections. Killed off the "beneficial buggies" that normally live in the GI tract and allows the Candida to get established and grow. If you need to take a long course of antibiotics, be darned sure to also take active acidophilus culture capsules.
Or probiotics.