Sarah carefully poured 1 cup of Liquid-Plumr into the dishwasher drain and let it sit for about an hour. She then ran a hot water cycle without any dishes or detergent. The Liquid-Plumr worked its magic, breaking down any grease and food residue that might be clogging the drain.
You will find forum posts from people who swear they ran a half-cup of Liquid Plumr through their dishwasher and it "cleared the drain right up." liquid plumr in dishwasher