Answer: heroin

AnswerCrossword Clue
HEROIN

Illegal stuff

HEROIN

Illegal substance

HEROIN

Speedball ingredient

HEROIN
Drug.
HEROIN
Narcotic.
HEROINDerivative of morphine.
HEROINDiamorphine.
HEROINNarcotic
HEROINNarc's concern
HEROINMorphine relative
HEROINAddiction source
HEROINJunk, so to speak
HEROINSmack, so to speak
HEROIN"Smack"
HEROINBayer creation of 1898
HEROINSpeedball component