Krusty's Non-Narkotik Kough Syrup

Krusty's Non-Narkotik Kough Syrup is a children's cough syrup that became the secret ingredient of the Flaming Homer.

History
When Homer was out of beer at home, he made a cocktail from several other alcoholic drinks. In his haste, he accidentally mixed in the cough syrup, inadvertently inventing the Flaming Homer.

Homer later shared the drink with Moe, and when a customer at the bar asked what it was called, Moe was quick to claim the drink as his own work, calling it the "Flaming Moe". After this, the drink became enormously popular and beverage companies tried to analyze the drink to duplicate it. They were able to figure out all of the components except the cough syrup, leaving the cough syrup as the secret ingredient.

Eventually, however, the secret was revealed. Homer had become increasingly frustrated and jealous over Moe's claiming the drink as his own. When the pressure became too great, Homer snapped, and, during a half-crazed rant in full hearing of a large crowd at Moe's Tavern, revealed that the cough syrup was the secret ingredient.