Many of us on CZ have had bad experiences with doctors regarding parasites. I suspect they are kind of clueless, on the average, about candida too. I believe you can get rid of parasites just fine w/o them and save your money. Not positive about candida, but I know I removed a great deal of it - & I could clearly see it as it left. Info on that below if you are interested.
Re the topic of enemas sometimes mentioned below, I am adding a personal feeling of caution about colonics - professionally done high colonic enemas. I have seen them really depleting people's energy, though some really like them. They do flush out a lot of good bacteria & probiotics along with the junk.
There is really no data that I know of to show that good bacteria can be replaced by over the counter supplements, or even things like acidophilus yogurt, kefir etc., after such a highly invasive wash of the intestines. Maybe so, maybe no, but there is new info coming out that low probiotics in the gut can cause things like Depression (see Dr. Mercola & Dr. Marsha Campbell’s Youtube vid for example) and even possibly things like autism if the mother's probiotics are too low and she doesn't pass enough onto her baby in the birth canal or through her milk.
I'm no expert on any of that, just presenting what I worry may be a potential hazard. Mho.