After much experimenting with them I can tell you that they kill candida all right but they also kill pretty much any kind of bacteria, good and bad. I'm of the opinion that taking essential oils is like taking penicillin or tetracycline. They push you further into dysbiosis, especially oregano oil. I remember reading an old post here on CZ that someone tested antifungals for their antibacterial properties and found that the only essential oil that did not profoundly effect the bacteria was peppermint oil. Peppermint oil is a good antifungal however. I use it with coconut oil and monolaurin. Very potent combination. 1/4 teaspoon peppermint oil, 3 tablespoons of coconut oil and 1 rounded teaspoon of monolaurin.

Oregano is probably the most powerful natural antifungals.
So it's an excellent choice for candida treatment. Indeed it has many other properties like antibacterial, antiviral...
As far as I understand it, Candida does not develop any resistance to Oregano compared to other products.

In my case where I had a suspected case of SIBO and Candida it was the perfect choice. It will kill Candida and at the same time lower the number of bacteria (not annihilate them)

With all these treatments the key is probably to not overdo it. Taking Oregano oil like some others products for a long period of time is probably not recommended. A 3/4 weeks treatment is safe (and that's not my opinion, I specifically asked my my GI who's probably in the top 5 in the country in terms of microbiota / micro-biome knowledge)

And btw Pau d'Arco (like other stuff) has also anti bacterial properties... So i believe it would be naive to think that it won't interfere with good bacteria somehow.

- R