AFP and hepatocellular carcinoma: For example, a phase I clinical trial of the natural flavonoid quercetin reported a sustained reduction in serum alpha-fetoprotein and alkaline phosphatase levels in a metastatic HCC patient treated with an intravenous infusion of quercetin (60 mg/m2).[158] Combined with findings from other cases, this study suggests that intravenous quercetin administration is feasible and safe.