go through someone like a dose of salts
go (right) through (one) like a dose of salts
Of food, drink, or medicine, to be rapidly excreted from the body (as urine or feces) very soon after being ingested. A reference to the use of Epsom salts as a laxative. I try not to drink more than one cup of coffee, it just goes right through me like a dose of salts! I love Indian food, but I eat it so infrequently that when I do, it goes through me like a dose of salts.