Neoheroin was a drug that was illegal in the Federation.
E.D. Fitzgerald visited an Orion spaceport and witnessed the unloading of 75 tons of neoheroin, which was quite legal under local regulations, though Fitzgerald was not told where it was going. He also saw a Human disguised as a Rigellian apparently attempting to steal some, though the thief was disabled when his nose-filters became clogged. Customs officers arrested him and expected to interrogate him for his associates, if he survived. (FASA RPG - The Orions module: Book of Common Knowledge)