Originally Posted by
Enkidoh
There is also a third illicit drug mentioned in the game called 'pluto', but it's unclear just what that term refers to, whether it's another term for somnus or a completely different drug (although the name itself seems to suggest the later, and a dangerous one at that).
Somnus is clearly shown to come from a purple-coloured plant that is being illicitly cultivated by the refugees in the caves near Black Brush Station (presumably they do it as a means of supporting themselves, despite the drug being illegal in all Eorzean citystates). And as mentioned, it is apparently a narcotic, having opium-like properties of drowsiness/lethargy, and is also highly addictive, not to mention deadly if overdosed.