Pau d'Arco, also known as Taheebo, Palo d'Arco or Lapacho is at home in the tropical regions of Central and South America. As a member of the Bignoniaceae or Trumpetflower trees, it is related to the Catalpa, which is a commonly grown decorative garden species, appreciated for its beautiful flowers. Native tribes of Central and South America have long valued this tree, not only for its strong, fungus and insect resistant wood, but also as a medicine. The Guarani Indians fashion their hunting bows from the wood in the hope that the tree's vigour will be transferred to both, bow and hunter. The medicinal use of Pau d'Arco is most common in Brazil where it is regarded as a virtual panacea. Medical practitioners began to take note, when a hospital doctor started to treat his dying brother, who was suffering from cancer, with this herb. Apparently, his treatment was successful and soon other doctors at the clinic joined his empirical research. Subsequent clinical research has focussed on isolated constituents of Pau d'Arco, as these can be more easily standardized and patented. However, these studies produced unsatisfactory results and were soon dropped. Since then reports on the efficacy of Pau d'Arco have varied widely, ranging from miracle claims, to warnings about potential dangers, leaving even the most discerning user somewhat baffled. One of the reasons for such variant reporting may be due to the fact that the supply of commercially available Pau d'Arco is not subject to stringent controls. Thus, a number of related species, some of which have no medicinal uses at all, are all sold as Pau d'Arco and processed into a variety of products, since the inner bark shavings of the red Pau d'Arco tree are a by-product of the timber industry.
Pau d'Arco is said to have anti-fungal, anti-microbial and immune stimulating properties, which are employed in the treatment of numerous conditions ranging from the common cold to HIV. Most commonly Pau d'Arco is used to treat Candida, an intestinal yeast infection that often causes vaginitis. It is also used in the treatment of chronic fatigue syndrome. The immune response stimulating properties seem to be most prominent at low doses. Not all active constituents of Pau d'Arco are easily soluble in water and the bark must be prepared properly as a decoction. Even so, some herbalists claim that pills are more effective. Pau d'Arco is also used as a supportive remedy in kidney and bladder infections and to treat rheumatism and arthritis. Some people appear to have had good results when using this herb as an anti-cancer agent, though it is difficult to verify such reports.
Native shamans use Pau d'Arco in energising aphrodisiac concoctions and as an adjunct plant in Ayahuasca brews. It is used in healing rituals and is generally regarded as rejuvenating tonic.