The function of CYP4F12 (cytochrome P450 family 4 subfamily F member 12, ENSG00000186204) is as follows. A cytochrome P450 monooxygenase involved in the metabolism of endogenous polyunsaturated fatty acids (PUFAs). 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 (CPR; NADPH-ferrihemoprotein reductase). Catalyzes the hydroxylation of carbon hydrogen bonds, with preference for omega-2 position. Metabolizes (5Z,8Z,11Z,14Z)- eicosatetraenoic acid (arachidonate) toward 18-hydroxy arachidonate (PubMed:11162607). Catalyzes the epoxidation of double bonds of PUFAs such as docosapentaenoic and docosahexaenoic acids (PubMed:16112640). Has low omega-hydroxylase activity toward leukotriene B4 and arachidonate (PubMed:11162645). Involved in the metabolism of xenobiotics. Catalyzes the hydroxylation of the antihistamine drug ebastine (PubMed:11162645). {ECO:0000269|PubMed:11162607, ECO:0000269|PubMed:11162645, ECO:0000269|PubMed:16112640}.