Ambrosia is being transported in a highly concentrated form. It needs to be processed before dispensing into vials and distributing. One dose (20 cm³ or 20ml) stops the symptoms of the Gray Death for 48 hours.
There is exactly one vial in the game - in a chemical lab on upper decks of PRCS Wall Cloud. You can deliver it to Stanton Dowd to help him with his sickness. It has no effect if you use it on yourself, other than being rewarded with the message, "Strange...nothing happens..."