Why does Pepto Bismol taste so awful?

I know a lot of medicines out there are just plain disgusting and make you want to vomit on the spot...but the public generally agrees Pepto Bismol ranks way up there on the chart of awfulness. I just wondered if there's some particular ingredient that makes it that way, or the way it's cooked, maybe...something! Where the Pepto Bismol get is hellish taste, I ask you!? D: