Salt in the digestive tract extracts water from the body by osmosis. Kala namak acts as a digestive aid in reversing constipation and allowing individuals to eliminate flatulence.http://www.wisegeek.com/what-are-the-me ... -namak.htm
I'm not sure what those two sentences have to do with each other. And I don't put much stock in Ayurvedic medicine. Also, does "eliminate flatulence" mean "make it go away" or "make you fart"?
i'm thinking the person who wrote it assumed everyone's fart backups come from constipation. (i know mine do.) so they were saying that because salt pulls water into the digestive tract, it reduces constipation and therefore fart backups. (i have no idea if i expel the same amount of gas during days that i have had a regular poop as on days that i haven't, but i assume yes? they just escape without any fanfare because they aren't blocked by all that poo.)