Pau d'arco

Pau d'arco
Pau d'arco

Pau d’arco (pronounced pow-darko) is a large tree that grows in the Amazon rain forest and in tropical areas of South America. The botanical names for the species most commonly used are Tabebuia heptaphylla and Tabebuia impetiginosa.

The tree is called taheebo or lapacho in South America. The inner bark of pau d’arco is used as an herbal medicine, most notably in the treatment of cancer and infections.

The pau d’arco tree grows up to 150 ft (45 m) tall and 10 ft (3 m) in diameter, and is prized for its lumber. The wood is extremely hard, and makes fine furniture. The tree produces large purple flowers, making it popular for landscaping and decoration. The bark of the tree has been used medicinally by native South American peoples for centuries. Rain forest medicine men scrape the inner bark and brew a tea from it.

The tea has been used to treat conditions as varied as malaria, infections, fever, arthritis, skin problems, syphilis, AIDS, and cancer. Pau d’arco has long been a common herbal remedy for Europeans who moved to South America as well, and is sometimes drunk there as a refreshing tea. The tea has a cool, bitter flavor.

Pau d’arco became known to the mainstream medical community during the 1960s. At that time, a doctor named Theodore Meyer learned of the herb from a rain-forest tribe, and used it to treat patients suffering from leukemia (cancer of the blood). He reported that the herb completely cured five cases of advanced cancer.

Then, a hospital in South America used a tea made from the herb to treat cancer patients, and reported that pau d’arco reduced pain and cured tumors in some patients. These stories made it to the press, and pau d’arco was touted around the world as a miracle cancer cure.

Pau d’arco caught the attention of American researchers and drug companies, and scientific studies on it were performed. Scientists isolated an active chemical found in the bark, and termed it lapachol. Several studies showed that lapachol was effective against cancerous tumors in rats, giving it promise as a cancer cure.

In 1974, however, the National Cancer Institute concluded that the amounts of lapachol required for beneficial effects against cancer in humans would result in toxic side effects, and stopped researching pau d’arco as a cancer treatment.

Although research in general did not support the huge claims made for pau d’arco, it continued to generate stories of miraculous cancer cures and other successes treating infections and chronic conditions.

Some researchers have theorized that other ingredients in the bark besides lapachol may have therapeutic effects; and it has been shown that the use of the whole herb does not create the side effects that extracted lapachol causes. Researchers have isolated over 20 active chemicals in pau d’arco.

Research, mainly on laboratory animals, has shown pau d’arco to have anti-microbial and anti-viral properties, helping to destroy bacteria, fungi, parasites and viruses by increasing the supply of oxygen to cells.

It has demonstrated effectiveness against yeast infections, malaria, tuberculosis, strep, and dysentery. Pau d’arco has also been shown to influence the activity of the immune system.

In small dosages, it increases immune system activity and in large doses suppresses some immune responses such as inflammation. Its anti-inflammatory actions have given pau d’arco promise as a remedy for allergies, arthritis, skin problems, ulcers and other inflammatory conditions.

General use

Pau d’arco is used frequently in the herbal treatment of cancer and infections, including candidiasis and other yeast infections. Pau d’arco is also used for allergies, arthritis, diabetes, flu, lupus, parasites, skin diseases, and ulcers.


Pau d'arco bark
Pau d'arco bark

Pau d’arco is available in health food stores in capsules, tinctures, and as dried bark. The recommended dosage is 1-2 capsules or 1-2 droppersful of tincture taken one to four times per day, depending on the condition and patient.

Tea can be made from the bark by adding 1 tbsp of bark for every 3 cups of water. The tea should be boiled for 20 minutes or longer in a non-aluminum pot. One cup of tea can be taken three or four times daily for acute conditions. One-half cup three or four times daily is recommended for other conditions.


Pregnant and lactating women should not use pau d’arco, as its effects during pregnancy have not been sufficiently researched. Pau d’arco has been shown to have blood-thinning actions in some people, and may cause anemia (shortage of red blood cells) when used over long periods.

For this reason, pau d’arco should not be used before surgery or by patients with anemia or bleeding problems. Another precaution consumers should take is assuring that the product they purchase is produced by a reputable manufacturer. Pau d’arco is a valuable resource in South America, and there has been a history of fraudulent products being exported.

Some of these products have caused uncomfortable side effects that do not occur with real pau d’arco. In Canada in 1987, a chemical analysis of 12 commercial products revealed that only one contained the active ingredient lapachol, and that was in minute amounts.

Some manufacturers have begun to offer products with standardized quantities of active ingredients to assure quality. The pau d’arco imported from Argentina is generally considered to be the highest quality bark.

Side effects

Possible side effects from ingesting too much pau d’arco include nausea, vomiting, diarrhea, dizziness, and stomach cramps. Long-term usage has been reported to cause anemia.


Pau d’arco products should be avoided by those taking anticoagulant (blood thinning) medication.