Pau d'arco is a tree that grows in the Brazilian rainforest. In Brazil the tree is called Tahuari and has been used by the indigenous people in the rainforest as a cure-all. Pau d'arco has two constituents that have interest to medical science: Beta-lapachone and lapachol which are topoisomerases that have been proven in medical science to be anti-cancer agents. However, there is a dark side: They can have side-effects of severe nausea and anemia. These two constituents in pau d'arco have been shown to help dramatically improve cancer patients with lung, breast, colon, prostate, malignant melanoma, HIV (level 1) and leukemia. However the nausea and anemia side effects have caused doubt in doctors' minds as to its effectiveness. Doctors have isolated two of pau d'arco's components and say they are great anti-cancer compounds but they are toxic at high levels. Herbalists believe in aiding and preserving nature, not changing it; therefore, they believe pau d'arco should be taken as an extract of a whole plant where it has no known toxicity levels, no nausea and no anemia - not as isolated compounds. It is naturally not as strong as taking 10 tons of plant material and extracting two of the hundreds of constituents and making it a concentrated pharmaceutical. However, taken as a tea or extract it has many wonderful benefits and someone with a serious illness, under a doctor's supervision, can take pau d'arco and see positive changes. Pau d'arco has been shown to help with pain and cancer. Cancer patients found themselves in remission after a 3-8 of months of using pau d'arco with supervised medical care. Dr. Theodore Meyer learned of pau d'arco's benefits and used it on his patients, and reported that 5 of his terminal leukemia patients were completely cured. “Beta-lapachone keeps the chromosomes wound tight, and so the cell cannot make proteins. As a result, the cell stops growing. Because cancer cells grow and reproduce at a much faster rate then normal cells, they are more vulnerable to topoisomerase inhibition than are normal cells. Beta-lapachone also interferes with the replication of HIV-1, a virus that causes AIDS, thereby slowing the advancement of the disease.” Maybe modern science will find a way to take out the components that cause side effects when you take highly concentrated forms of compounds isolated from pau d'arco. Scientists have discovered 3-allyl-beta-lapachone, a chemical relative to beta-lapachone, that has been found to have lower toxicity levels in cell culture tests, and might be proven to be more effective. However, more tests will need to be done so that doctors and scientists might be able to come up with an effective “cocktail,” like they do for HIV and AIDS patients. This would create a combination to balance the side effects with other herbs that could reduce the nausea and anemia, and which has no contra-indications when taken with pau d'arco. For instance, there are two traditionally used herbal extracts that are effective when taken internally for severe nausea: Chamomile flower and nutmeg. Further, dandelion root has extremely high iron content and might help combat the anemia. This research article was written to create awareness and provide consumers with a general overview of available scientific information. For further interested reading, there is a 152-page book called Pau D'Arco by Kenneth Jones that is recommended by the American Botanical Council. It is available from Amazon.com for $7.50.