Strobolin
Strobolin was the cure for the choriocytosis virus. 

It was a rare, naturally-occurring substance only found on a few planets in the Milky Way Galaxy. Given the extremely rapid and deadly symptoms of choriocytosis in species with blood not based on iron, such as Vulcans, ships working in coordination were sometimes necessary to deliver the medication to stricken individuals in time. A synthesized version of the medication could be used to slow the progress of the disease, but the recipient became immune to its effects within a few days.

When Spock contracted the virus in 2270, the  obtained the drug and delivered it to the . En route to the  to deliver the drug, the Huron was attacked by Orion pirates, who stole the drug and the ship's other cargo, dilithium. 

Captain James T. Kirk later offered an Orion captain the dilithium shipment carried by the Huron as well as an additional galactic standard weight container of dilithium in exchange for the strobolin that the Huron was bringing them, as they desperately needed it to cure Spock's choriocytosis. 

The Enterprise eventually recovered the drug and Doctor Leonard McCoy administered it to Spock, saving his life. ()

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