plantae lamiales verbenaceae stachytarpheta jamaicensis

porterweed
worrywine

The fresh leaves are consumed in bush tea as a “cooling” tonic and blood 
cleanser, to treat “asthma” and “ulcerated stomachs”.

Tea brewed from this species has been shown to cause a dose-dependent "fall in 
[the] blood pressure" of normal rabbits. However, the tea has also been 
observed to cause a "mild non-dose dependent systematic toxicity" in various 
tissues throughout the body, "such as congestion, fatty changes, and necrosis 
in liver, blood vessels, kidney, lung and testis, but the brain, eyes, 
intestines and heart were essentially normal."

REFERENCE:
http://en.wikipedia.org/wiki/Stachytarpheta_jamaicensis