- "What happened next [after giving Doc wake-up juice] was quite amazing. In fact, Marty couldn't figure out what was most incredible — the strength of Doc's bloodcurdling scream, the amazingly blood-red color of his face, or the speed with which he ran from the bar to dunk his head in the horse trough. / Well, no matter which was most surprising, the final effect was quite dramatic. Marty and the barkeep both ran out of the bar to find Doc's head totally submerged in water! / Marty heard a gulping sound from the trough, and realized that Doc must be drinking water. He hoped, when this was all over, that his friend would forgive him for this dramatic cure."
- —From Back to the Future Part III by Craig Shaw Gardner (quote, pages 163 and 164)
A horse trough, or watering trough, was an open stone receptacle which provided drinking water for horses.
When Emmett Brown passed out after drinking whiskey on September 7 after losing Clara Clayton and had wake-up juice poured into his mouth by Chester, it is fortunate indeed that the trough was there — bearing in mind that the effects of the aforementioned concoction made it necessary for Doc to dunk his head in water immediately afterwards.