PP Candy (PPキャンディー) (Sweetrots in the manga) is a medicine made by Bulma.
Bulma used the PP Candy, disguised as a vitamin, to make Oolong obedient. She tricks him into eating it, but after he eats it, any time she yells "Piii Piii!", he would have stomach cramps and diarrhea. In other dubs, she yells "Piggy!" and in the manga she whistles "Swee!" (a call used by farmers to let pigs know when it's feeding time).