Since the early 1980s, Pau d Arco has been sold in health food stores in the United States, where it is promoted as a treatment for virtually every kind of medical complaint, including arthritis, ulcers, diabetes, and cancer. Taken internally, it is thought to relieve infections, reduce inflammation, and promote good digestion.
Anecdotal reports claim that it causes tumor regression.
Another uncontrolled study found that, out of nine patients taking oral doses of lapachol for three or more weeks, one had complete tumor regression and two had partial regression. Unconventional cancer treatments. Recognition and evaluation of lapachol as an anti-tumor agent. Walker 256 rat carcinosarcoma showed sensitivity to lapachol by daily intraperitoneal injection at levels up to those producing limited toxicity. Lapachol exhibited marked effectiveness by oral route of administration with best activity shown with twice a day oral administration on Days 3-6.