this may be of some use:

[URL unfurl="true"]http://www.herbalayurveda.com/downloads/vacha.pdf[/URL]

as I understand it, acorus calamus is used in higher doses to induce purgation....i think a tea, sometimes with a few other herbs.

i think i've tried a tea once, but honestly, the better way seems to be just chewing pieces of the root. this would at least avoid the GI tract for the most part, aside from swallowed saliva.......i get mental effects from chewing it....but it's not an herb i regularly use, because of it's pungent, drying nature.

it's definitely got it's effects on the nervous system though. as with any herb, it's all about preparation and herb quality.