To treat a host of ills ranging from fungal infections to the common cold, traditional healers in South and Central America have long brewed a tea made from the inner bark of a native evergreen tree of the Tabebuia species.

Today, this healing brew, variously referred to as pau d’arco or Taheebo, is readily available in North American health-food stores and sold as a “cure” for cancer and numerous other ills (including diabetes, warts, and vaginal yeast infections). Whether pau d’arco actually works for any of these conditions is unclear and the subject of ongoing confusion and controversy.