Methods for protection of a human from SVFS comprise the administration of a flavonoid compound of the basic structures 2-phenyl-4H-1-benzopyran or 2-phenyl-4-keto-1-benzopyran or glycosides thereof, alone or, optionally, together with one or more of an olive kernel extract, a non-bovine sulfated proteoglycan, bitter willow extract, a D-hexosamine sulfate, S-adenosylmethionine, folic acid, vitamin B12 and a serotonin inhibitor. Such treatment prevents, reduces or eliminates SVFS in patients receiving as much as 300-3000 mg/day of niacin therapeutically, whether administered prior to, or along with, an anti-SVFS composition.