Ayahuasca is an amazing medicine. If you decide to do it, do it in the Peruvian Amazon, read the reviews carefully of each retreat center before you decide on which one to go to. Follow the diet and any other restrictions, this is especially important AFTER drinking ayahuasca. The shaman will tell you what to avoid and for how long. Don't use kambo, bufo or rapé before, during or after the retreat, it will interfere with the treatment. A lot of vendors in Iquitos will try to convince you that it's good to combine rapé with ayahuasca, but it isn't. Ayahuasca works best alone. Basically you should only be doing ayahuasca (and mapacho if you like to smoke).
It's a very powerful medicine and if you drink with someone with bad intentions it can be very dangerous.