Pau d’arco is an herbal extract obtained from the inner bark of the Tabebuia avellanedae or Tabebuia impetignosa trees, also known as taheebo trees, which grow in Central and South America. Other names are ipes, ipe roxo, lapacho, tahuari, and trumpet bush. Alternative medicine practitioners claim pau d’arco has antiviral and antibiotic healing properties and may fight cancer.
Pau d’arco is growing in popularity in the United States and Europe as a treatment for many illnesses and diseases. The extract may be obtained from several companies and is sold as a powder, tablet, capsule, tincture, or tea in many health food stores and on the Internet.
The indigenous peoples of Central and South America are believed to have used taheebo tea for thousands of years to treat dozens of diseases and illnesses. Poultices of the bark are used to treat skin infections and wounds. Results of informal studies in Brazilian hospitals in the 1960s claimed that cancer patients drinking taheebo tea were completely cured. The claims stimulated interested in the herbal extract and more formal studies were performed over the next decade.
The herbal extract contains lapachol, beta-lapachone, and 20 other possible active ingredients that may have multiple health benefits. Most studies have focused on lapachol and beta-lapachone as possibly being effective against cancerous tumors. Several studies have shown anti-tumor activity on specific types of cancerous tumors.
Pau d’arco can have toxic effects at high doses. In one study involving cancer patients, 1,500 mg of lapachol per day caused nausea, vomiting, anemia, and increased risk of bleeding. Many studies have been terminated due to severity of side effects. It is possible that pau d’arco may not be tolerated at dosages high enough to deliver benefits.
Many herbalists claim that toxic reactions that are common when the active ingredient is extracted are not present when the whole bark is used. Researchers stopped studying the substance in 1974 due to toxicity. In 1984, Canada banned the use of pao d’arco.
Despite the controversy, demand for pau d’arco products continues to grow. The manufacturing of pau d’arco is largely unregulated and there have been reports of disreputable manufacturers distributing products that do not contain the active ingredients that make the substance effective. There are around 100 varieties of Tabebuia trees, bearing similar names, but without the active ingredients found in Tabebuia avellanedae and Tabebuia impetignosa. In the U.S., the substance is sold as an herbal supplement, meaning it does not have to undergo FDA approval for its health claims.