Cocaine

From Wiki 24

Cocaine is a stimulant drug with powerful, but short-lived, effects.

[edit] Day 3

Kyle Singer thought he was bringing cocaine across the border from Mexico, when in fact it was simply harmless, white powder. He was used in the sting operation performed by Jack Bauer, Tony Almeida and Gael Ortega to trick CTU into thinking that it was the Cordilla virus, so as to distract them whilst Jack broke Ramon Salazar out of prison.