It is within the mountainous provinces of Hamgyong and Ryanggang that Opium production is said to have first flourished within North Korea in the 1970's under the watchful eye of Kim Il-sung.
Since that time, North Korea has come to produce some 40 tonnes of Opium per year throughout these mountainous provinces. Much of it is either smuggled raw into neighbouring China or refined into Heroin to be trafficked worldwide, with one of the most notable instances being an intercepted shipment of over 100 kilos of high grade Heroin bound for Australia.
Other drugs the North Koreans concern themselves with are Cocaine, Clonazepam, Rohypnol and Methamphetamine. The latter of which is supposedly prescribed to ailing members of North Korean communities as a sort of cure-all medicine or ingested by the wives of Party members who are eager to diet.
This is similar to what we saw in the mass Amphetamine prescriptions of Nazi Germany during the 1940's.
Rumours abound these days of whether or not North Korean drug trade continues or has ceased in similar fashion to how counterfeit currency mysteriously disappeared for a brief period. Given the difficulties currently being faced by the countries economy and populace at large it is feasible that drug trade in the hermit kingdom is alive and well.