Wisdom of the Ancients Pau d'Arco (Purple Lapacho) Herbal Tea Bags all-natural, extraordinarily healthful herbal tea is known for its ability to boost immunity. Skillfully hand-harvested by Paraguayan experts, the inner bark of the Purple Lapacho tree, properly cured and cared for, yields naphthoquinones, anthraquinones and other phytopharmaceuticals, including quercetin, that generate remarkable health-promoting benefits.