Yea, back in the 70's I had a friend who was a pharmacist. Unfortunately, he found himself hooked on speed. DOC was what we used to call "Christmas Trees", which were capsules with one side green and the other was white (or clear, I don't remember).
I believe the white and green "Christmas Trees" were Dexamyl spansules, an extended-release formulation containing both Dextroamphetamine and Amobarbital.
The same moniker was also applied to Tuinal, which was a gelcap filled with a mix of Amobarbital and Secobarbital, which were apparently named for their bright blue-and-red coloration (think Vyvanse 70 mgs).