Source Naturals PAU D’ARCO is derived from the inner bark of the Purple Lapacho tree found in Brazil and Northern Argentina. Ever since ancient times, when it was a standard for the medicine men of the Inca Empire, pau d’arco (also known as ipe roxo and taheebo) has been one of the most widely used herbs in South America. The Guarani and Tupi people of South America call the tree tajy, meaning “to have strength and vigor,” and have traditionally used the bark to support respiratory function and the body’s healthy inflammatory response.*