Green’s Dictionary of Slang

B-and-Q n.

[abbr.; ult. punning on the DIY superstore B&Q]

(US drugs) a mixture of bonita and quinine sold as counterfeit heroin.

[US]Simon & Burns Corner (1998) 69: Baking soda or bonita-and-quinine — B-and-Q — as dope, oregano as weed, battery acid as ready rock.