For thousands of years the inhabitants of Brazil, northern Argentina, Paraguay, Bolivia and Peru have been using pau d'arco - lapacho (T. impetiginosa). It is probable that even before the Inca times they were using it against cancer, syphilis, malaria, Chagas disease (trypanosomiasis), fungal and bacterial infections and stomach ailments. When the Spanish and Portugese colonists came to South America they noted that many indigenous groups such as the Guarani, Tupinamba, Kallawaya, Quechua, Aymara and others consumed large amounts of pau d'arco.
Dr Joaquin Almeida Pinto, writing in 1873, described many healing properties of pau d'arco (Tabebuai impetiginosa): ‘Pau D'Arco: Medicinal Properties: prescribed as a fever-reducer the bark is used against ulcers, also used for venereal and rheumatic disorders and especially useful for skin disorders, especially eczema, herpes and the mange’
Clinicians renewed their interest in pau d'arco (Tabebuai impetiginosa) in 1967 when the Brazilian newspaper, O’Cruzeiro dated 18 and 25 March 1967r reported the ‘miraculous’ recovery of cancer patients in hospitals in São Paulo and Santo André. The O’Cruzeiro journalists tracked down the biggest advocates of pau d'arco: firstly Dr Valtera Accorsi, retired professor and botanist from the University of São Paulo and secondly Dr Orlando dei Santi.
Dr Orlando dei Santi, quite by chance, learned of the story of a young girl in Rio who had been suffering from advanced cancer and whose doctors had not been able to help her. When the girl had started drinking pau d'arco, she had initially felt less pain caused by the disease, and then the cancer had disappeared altogether. When Dr dei Santi heard about this he went back to Santo André hospital where his own brother, also with cancer, was nearing his death. Against all the advice that the doctor had received at his medical college about not using the not scientifically verified methods and ways of the Indian tribes, Dr dei Santi decided to test pau d'arco on his dying brother. It is said that Dr dei Santi concocted an infusion of dry pau d'arco bark with white wine which he then mixed with orange juice and gave to his brother. After drinking the mixture for a month Dr dei Santi’s brother was discharged from hospital with no sign of cancer. Dr dei Santi then started treating other patients with pau d'arco and the practice became popular with other doctors in the hospital.
More or less at the same time as Dr dei Santi was treating his brother, the O’Cruizeiro journalists approached Professor Accorsi who was, at that time, on his way to Piracicaba. There, he had been treating some 2000 people a day with pau d'arco bark tea. When he heard of the Rio cancer girl story he started examining the pau d'arco trees in his home state of São Paulo, and comparing the results with those from the states of Bahia and Pernambuco. When he looked at the effect on leukaemia patients he noticed that the Bahia trees had a stronger effect. He also confirmed that pau d'arco tea had an anaesthetic effect and caused a significant increase in red blood cells.