A simple and rapid spectrophotometric method for the determination of artemisinin (ART) and dihydroartemisinin (DHA) is described. The method is based on the reaction of hydrogen peroxide (H2O2), generated by the cleavage of endoperoxide linkage of ART/DHA and its reaction with potassium iodide to liberate iodine. The liberated iodine bleaches the red coloured safranin O to colourless species and is measured at 521 nm. Beer's law is obeyed in the range of 16-112 mu mg mL(-1) for both ART and DHA. The molar absorptivity, Sandell's sensitivity, detection limit and quantitation limit for ART were found to be 0.3401 x 10(4) Lmol(-1)cm(-1), 1.43 x 10(-2) mu g cm(-2), 0.0685 mu g mL(-1) and 0.2075 mu g mL(-1) respectively; while that for DHA were found to be 0.2891 x 10(4) L mol(-1)cm(-1), 1.33 x 10(-2) mu g cm(-2), 0.0491 mu g mL(-1) and 0.1488 mu g mL(-1) respectively. The optimum reaction conditions and other analytical parameters were evaluated. The statistical evaluation of the method was examined by determining intra-day and inter-day precision.