Infra-Sensory Drugs
From Star Trek : Freedom's Wiki
In the late 23rd century, infra-sensory drugs were part of therapy employed to cure violent offenders at the Tantalus Penal Colony. In 2266, the USS Enterprise delivered two containers of these drugs to that colony. (TOS: "Dagger of the Mind")
The drugs were shipped in containers bearing a cautionary label. This could mean the drugs were dangerous, but the crewman handling them wore no special protective gear. It could also mean they were valuable, or that they required special handling and storage.