Just as Roger Rabbit shows us the good and bad sides of laughter, it also shows positive and negative effects of liquor. Eddie Valiant has a drinking problem that, unlike Ted Striker's in Airplane!, is no laughing matter.
We covered Eddie's whiskey dependence in his character profile, so here we want to show one smart way Eddie uses liquor to his advantage.
It makes Roger explode.
He's a Toon, so it's okay. But he definitely cannot hold his liquor. When Roger's in tears over Jessica, Maroon offers him a drink. It causes Roger to blow his stack and go off like a train whistle, before zipping through the wall, leaving only a Roger-shaped hole.
This reaction comes in handy later, when Roger's caught by Doom in Dolores' bar. Doom's about to execute Roger, and Eddie offers him one last drink. After some dizzying reverse psychology, Roger agrees to do a shot…and he goes off like a shot. It creates a diversion, freeing him and allowing Eddie and him to escape. ( It's not good for everybody, though: poor Dolores has to clean up the mess.)