In alt.food.mexican-cooking Dimiri wrote:

Epazote!

Sage also works well, but the line between best results and "I can
taste the sage in my beans!" is kinda narrow. And some females are
sensitive to the stuff and will start their menstrual periods a day or
two after eating too much (for them) sage.

--
Art Sackett,
Patron Saint of Drunken Fornication