Only if you suffer from preexisting heart problems or if you are pregnant. Otherwise, if prepared properly, and administered by a knowledgeable Spiritual Guide/Shaman, there is absolutely no danger from an Ayahuasca ceremony. To date there has been no negative physical or psychological side effects to continued use of properly prepared Ayahuasca.
The concern that has recently arisen in relation to Ayahuasca is due to fake Shaman with dangerous brews. This has been a consequence of its growing popularity and a lack of regulation. Many experienced Shaman will add a plant to the brew called “toé” to increase the hallucinogenic effects of the Ayahuasca.
But, if used in excess, toé is extremely dangerous and can cause permanent mental impairment and even death. You should always do your homework before venturing into the Amazon and trusting anyone who calls themselves a Shaman. Its recommended Ayahuasca´s cerimonies to those people that may have an intention of healing, the Ayahuasca it´s a divine medicine and it wouldn’t be dangerous to anyone.