Pau d"Arco extract (Tabebuia impetiginosa) is derived from the bark of a giant hardwood tree that is native to the Amazon rainforest in South America. Also known as "Purple Lapacho" - Pau d"Arco trees are virtually immune to attack from fungi, parasites and disease, and bark infusions have been used by many rainforest tribes for over two thousand years to maintain a healthy immune system.