I was assuming it was a reference to a barium enema, which is a medical test involving getting a lot of barium into your intestines so they will show up in X-rays better. Pretty much everything about the test and its preparation would fall under "unsavory," I suspect.
And the "come and choke on it" line would make sense in that context since the patient has to (among other things) drink a large quantity of barium sulfate solution. I've had a couple of relatives go through it and it's pretty loathsome.