The function of CYP2B6 (cytochrome P450 family 2 subfamily B member 6, Ensembl gene identifier ENSG00000197408) is as follows. A cytochrome P450 monooxygenase involved in the metabolism of endocannabinoids and steroids (PubMed:12865317, PubMed:21289075). Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (NADPH--hemoprotein reductase). Catalyzes the epoxidation of double bonds of arachidonoylethanolamide (anandamide) to 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid ethanolamides (EpETrE-EAs), potentially modulating endocannabinoid system signaling (PubMed:21289075). Hydroxylates steroid hormones, including testosterone at C-16 and estrogens at C-2 (PubMed:12865317, PubMed:21289075). Plays a role in the oxidative metabolism of xenobiotics, including plant lipids and drugs (PubMed:11695850, PubMed:22909231). Acts as a 1,4-cineole 2-exo- monooxygenase (PubMed:11695850). {ECO:0000269|PubMed:11695850, ECO:0000269|PubMed:12865317, ECO:0000269|PubMed:21289075, ECO:0000269|PubMed:22909231}. Allele 2B6*9: Has low affinity for anandamide and can only produce 11,12 EpETrE-EAs. .