Pau d'arco (Tabebuia avellanedae and related species) is a tree native to South America whose inner bark has been used traditionally in herbal medicine. Its primary historic uses have centered around its purported antimicrobial, antifungal, and anti-inflammatory properties, particularly in folk medicine of Brazil and neighboring countries. Traditional practitioners have sometimes used pau d’arco teas or extracts to “cleanse” the blood or support immune function, which is occasionally extended to claims of "supporting the lymphatic system." However, these uses are based on empirical tradition rather than direct evidence or a well-documented mechanism involving the lymphatic system specifically.

Scientific research on pau d’arco has focused mainly on its naphthoquinone compounds (such as lapachol and beta-lapachone) for their potential antimicrobial and anti-tumor effects, but studies directly evaluating effects on the lymphatic system or lymphatic health are lacking. There is no robust clinical or preclinical evidence to support pau d’arco’s use for lymphatic system support, and its traditional use for this purpose is not well established or prominent compared to its other uses. Thus, while some herbal traditions may mention it in the context of "detoxification," the evidence remains weak and largely anecdotal.