Immunomodulating effects of Hypoxis hemerocallidea, Sutherlandia frutescens and standard compounds found in these plants were determined. Neither of the extracts, nor the standard compounds were cytotoxic to THP-1 and U937 macrophages. Antioxidant activity of H. hemerocallidea was equivalent to 0.2 mg/mL Trolox. Canavanine showed antioxidant activity comparable to that of curcumin (positive control). Curcumin (9.2 μg/mL) and beta-sitosterol (12.5 μg/mL) reduced IL-1β and IL-8 production significantly (p < 0.05) and decreased the production of TNF-α. Beta-sitosterol (25 μg/mL) and pinitol (50 μg/mL) significantly (p<0.01) decreased extracellular PGE2 levels in U937 macrophages by 12 % and 14 %, respectively. From the current results it would appear that the standard compounds present in the plants are far more effective in modulating the immune system than the extracts.