Green’s Dictionary of Slang

1. (drugs) the kit (eye-dropper, needle, spoon etc) used by a narcotic addict for injections.

1938		D. Maurer ‘Lang. of the Und. Narcotic Addict’ Pt 2 in Lang. Und. (1981) 99/2: The biz, bizz, or business. 1. An outfit for taking drugs hypodermically; it consists of a hypodermic needle or some homemade substitute, a medicine-dropper, a cooking-spoon, and a piece of cotton for filtering purposes.
1949		Monteleone Criminal Sl. (rev. edn).
1953		Anslinger & Tompkins Traffic In Narcotics 303: biz. The business: the hypodermic needle used by the addict.
1959		J.E. Schmidt Narcotics Lingo and Lore.
1971		E.E. Landy Underground Dict. (1972).
1992		Bentley & Corbett Prison Sl. 80: Biz The paraphernalia a drug user utilizes to inject heroin and other drugs. A person’s ‘biz’ usually consists of a hypodermic needle and syringe, a spoon, a tie-off or tourniquet, cotton and matches.

2. a bag or portion of drugs.

1938		D. Maurer ‘Lang. of the Und. Narcotic Addict’ Pt 2 in Lang. Und. (1981) 99/2: The biz, bizz, or business. 3. Narcotics.
1971		E.E. Landy Underground Dict. (1972).
2001		ONDCP Street Terms 3: Biz — Bag or portion of drugs.