Pau D’Arco

Supplements · Immune & Antimicrobial Herbs · Supplement, Typed Supps

A bitter bark tea from South America, traditionally called lapacho or taheebo, used for centuries in folk medicine.

Stage by stage

Intake (Bark tea or capsule): Traditionally brewed as a simmered bark tea.
Stomach & intestine (Absorbed): Naphthoquinones like lapachol absorbed through the gut.
Bloodstream (Circulates): Carried through the blood throughout the body.
Immune and microbial targets (Lab-demonstrated activity): Shows antimicrobial and cytotoxic activity in lab studies, not yet confirmed in controlled human trials.

What the evidence supports

Treating infections, cancer, or inflammatory conditions in humans — insufficient evidence. Antimicrobial and anticancer activity of its compound lapachol is well documented in vitro and in animal models, but rigorous human clinical trials for these uses are lacking; most human data are limited to small safety and tolerability studies, not efficacy trials.
Reducing menstrual pain (dysmenorrhea) — insufficient evidence. A single small open-label trial (12 women, no control group, 1050mg/day for 8 weeks) reported pain-score improvements alongside moderate tolerability, but without a placebo comparison this can't establish real efficacy versus expectation or natural symptom variation.
Evidence on Bleeding risk and toxicity at higher doses — limited evidence. Lapachol has documented anticoagulant activity and, in animal toxicology studies, caused anemia, abnormal clotting, and kidney stress at high doses; human case reports describe nausea, vomiting, and bleeding-related symptoms with excessive intake.

Typical dose

No standardized effective dose exists; traditional tea preparations use roughly 15g of inner bark simmered per liter of water, and the one controlled-tolerability human trial used 1,050mg/day of encapsulated bark for 8 weeks.

Upper limit: No established UL; safety literature notes side-effect risk rises with higher lapachol intake, and high concentrated doses of isolated lapachol have caused serious toxicity in case reports — a good reason to stick to mild traditional tea strength rather than concentrated extracts.

Timing

No validated efficacy dose exists; traditional tea is a much milder exposure than concentrated extracts.

Time to effect

Unclear: No controlled human trials establish a time-to-effect for any proposed benefit.

Common myth

“Pau d’arco is a proven natural cancer treatment.” In reality: Its anticancer activity has only been shown in lab dishes and animal models — there’s no controlled human trial evidence it treats cancer, and using it instead of proven medical care would be risky.