This is kind of a bizarre case but a 65-year-old man started losing his sight when the vodka he drank reacted with his diabetes medication. He regained his vision when he was given some expensive whisky. The man had been drinking some vodka at a party when his vision suddenly went away. He tried to sleep it off but it still hadn't come back by the morning.
When he got to the hospital, they diagnosed him with formaldehyde poisoning, which is associated with drinking methanol; which can be counteracted by ethanol, the kind found in alcoholic beverages. Because they didn't have enough ethanol in the hospital, they went and bought a $55 bottle of whisky and put it straight into his stomach. The man woke up 5 days later with his vision back.