A side affect of chewing betel nut (fig.) is the staining of the teeth by a black lacquer-like deposit, as with this man of the Black Lahu tribe and with the woman on the picture below, of the Akha tribe.

However, the substances in the seed do have benefits, as they speed up the functions of the heart and improve digestion, whilst the gums and palate are strengthened, and possible intestinal worms killed −possibly together with the libido of ones partner...