Antidote is a substance that can counteract the effects of poison.
In 1935, Indiana Jones was poisoned by Lao Che at Club Obi Wan when the gangster reneged on his deal to trade the Peacock's Eye diamond for Nurhachi's ashes. Lao Che produced a vial of blue antidote to force Jones into returning the diamond so Lao Che kept both artifacts.
A brawl broke out as Jones desperately tried to retrieve the antidote which got picked up by the club's singer, Willie Scott. Jones grabbed Scott and the pair leapt through a window, landing in a 1934 Duesenberg Auburn convertible several stories below. Jones drank the antidote in the ensuing car chase as the archaeologist, Scott, and driver Short Round fled to Nang Tao Airport.