Rooibos flavonoids and tannin, as well as aqueous extracts and crude phenolic fractions of unfermented and fermented rooibos (Aspalathus linearis) were evaluated for their capacity to scavenge α,α-diphenyl-β-picrylhydrazyl (DPPH ) and superoxide anion (O 2 - ) radicals. The relative potency of rooibos flavonoids towards DPPH decreased in the order: quercetin >= procyanidin B3 >= orientin >= luteolin >= aspalathin ~ isoquercitrin > iso-orientin catechin > rutin vitexin >= chrysoeriol. A different order was obtained for O 2 - : quercetin ~ aspalathin > orientin >= catechin >= rutin >= isoquercitrin > iso-orientin > luteolin > chrysoeriol > vitexin. Aspalathin was more effective than Trolox, the water-soluble analogue of α-tocopherol. Ethyl acetate solubles of the aqueous extract of unfermented rooibos and the crude aspalathin fraction, with the highest total polyphenol and aspalathin contents, had the greatest anti-radical capacity. Rooibos tannin, lowest in total polyphenol content, was the least effective radical scavenger. Fermentation decreased the anti-radical capacity of the aqueous extracts and crude phenolic fractions.