Stachytarpheta cayennensis, commonly known as blue porterweed, has been used in traditional medicine systems in parts of Africa, the Caribbean, and South America for various ailments, including urinary tract infections (UTIs). Ethnobotanical surveys and traditional medicine literature often cite the use of infusions or decoctions made from the leaves or aerial parts of the plant for symptoms suggestive of UTIs, such as painful urination or increased urinary frequency. The rationale in these systems typically relates to the plant's purported diuretic and anti-inflammatory properties, which are believed to help "cleanse" the urinary tract.

However, direct scientific studies validating the efficacy or mechanisms of Stachytarpheta cayennensis specifically against pathogens responsible for UTIs are scarce. Some preliminary phytochemical analyses have shown that the plant contains flavonoids, phenolic compounds, and other constituents that may have general antimicrobial or anti-inflammatory effects. A few in vitro studies have demonstrated mild antibacterial activity of extracts against certain bacteria, but these do not directly address major UTI pathogens nor provide clinical relevance. No robust clinical trials or animal studies specifically supporting its use for UTIs have been published as of 2024.

In summary, while there is a traditional basis for the use of Stachytarpheta cayennensis in urinary complaints, scientific validation is limited and the evidence supporting its effectiveness for UTIs is weak.