The inner bark of the lapacho tree plays a central role in the herbal medicine of several South American indigenous peoples. They use it to treat cancer as well as a great variety of infectious diseases.

There has been very little scientific investigation of lapacho as a whole herb. However, an enormous amount of scientific interest has focused on three constituents of lapacho: lapachol, lapachone, and isolapachone. The relevance of these findings to the use of lapacho itself remains unclear.

What Is Lapacho Used for Today?

Based on its traditional uses, lapacho is sometimes recommended by herbalists as a treatment for cancer . However, there is no reliable scientific evidence that the herb is effective. Test tube studies have found that lapachone can kill cancer cells by inhibiting an enzyme called topoisomerase , and there are hopes that effective anti-cancer drugs may eventually be produced through chemical modification of lapachone. 4-11 Nonetheless, this does not indicate that lapacho is effective against cancer in humans; it would be difficult to take enough of the herb to provide active levels of lapachone.

Similarly, test tube studies have found that constituents of lapacho (especially lapachone, isolapachone, and lapachol) may be able to kill various microorganisms, including various fungi and the parasites that cause schistosomiasis, malaria, and sleeping sickness. 12-16 These findings have led to the widespread belief that lapacho is useful against the yeast Candida albicans , a common cause of vaginitis , as well as the purported condition colloquially known as chronic candida ; unfortunately, the supporting research remains far too preliminary to meaningfully show clinical benefits.

Similarly, these studies have been twisted to support claims that lapacho is useful for many infections, including colds and flus and bladder infections . However, there are at least two problems with this reasoning. First, lapacho has been tested primarily against fungi and parasites; there is little evidence that it can kill viruses (the cause of colds) or bacteria (the cause of most bladder infections). Furthermore, even if lapacho can kill these microorganisms on direct contact, this does not imply that it would be effective if taken by mouth. Consider this analogy: wine easily kills the cold virus on direct contact, but if you drink wine when you have a cold you’re not likely to get well faster. Similarly, hundreds of herbal products kill microorganisms in the test tube, but fail to prove effective as systemic antibiotics. A substance taken by mouth has to survive the digestive tract and passage through the liver, and reach sufficient concentrations in the bloodstream to produce a meaningful effect. Few substances can do this without simultaneously proving toxic to the body; that’s why antibiotics were not invented until the 20th century and remain difficult to invent even today. Until lapacho’s potential effects as an oral antibiotic are examined directly, it is not reasonable to assume that the herb is likely to help systemic infections.

Lapacho and its constituents have also been investigated for potential use in the treatment of pain, 17psoriasis , 18 and ulcers ; 19 however, the evidence for benefit is as yet too preliminary to rely upon at all.

Dosage

Lapacho contains many components that don't dissolve in water, so making tea from the herb is not the best idea. It's better to take capsulized powdered bark; a typical dose is 300 to 500 mg 3 times daily. The inner bark of the lapacho tree is said to be the most effective part of the plant.

Safety Issues

When taken in normal dosages, lapacho has not been found to cause any obvious side effects. 3 However, full safety studies have not been performed. Furthermore, the anti-cancer actions of lapachone raise serious concerns about the safety of lapacho for pregnant women, because like cancer cells, cells of a developing fetus rapidly divide. Also, a study in animals found that lapachol caused fetal death. 20 For all these reasons, pregnant or nursing women should not use lapacho. Safety in young children or those with severe liver or kidney disease has also not been established.