The genus Tabebuia has over 100 species but one of the best know is pau d'arco (Portuguese), palo de arco (Spanish), purple lapacho (English) or bow wood. It is an extremely useful lumber tree and the Amazon Indians used it commonly to make their bows.
Although lapacho has a wide range of medical uses, it first came to public view because of its success in treating certain established cancers and as a cancer preventative in Brazil. The part of this beautiful tree used medicinally is usually the inner bark. If all the bark is removed, the tree dies. The more knowledgeable indians would remove a strip of bark from the trunk and allow this to heal before taking another strip thus preserving the tree for the future.
This herbal preparation is mainly used as a remedy for cancer, leukemia or cancer preventative; against fungal or yeast infections; against colds, flu and other upper respiratory bacterial and viral infections; against malaria and leishmaniasis; to control sexually transmitted diseases; as well as against psoriasis and dermatitis.
The writer personally uses this herbal as a bark infusion daily. Although I started using it as a cancer preventative and knew nothing of its other properties, I soon noticed that I had greater physical resistence, increased sexual libido and a facial skin problem became greatly reduced. In over two years of taking this I went from 4 or 5 colds a year to one very mild cold in 2 years. I am convinced if mankind had to be limited to only one herbal remedy, it should be pau d'arco.
See the Raintree link below for far more information.