[en] In this experiment, callus growth of L. erythrorhizon was increased by exposing to light but the shikonin production was increased in darkness condition and the effects could be increased by irradiation of low dose of gamma radiation. These results suggest that callus growth was the highest when callus was irradiated by 8 Gy of γ-ray and cultured on LS medium contained 2 mg/L BA and 2 mg/L NAA under 16 hours day light, however the production of shikonin form callus of L. erythrorhizon could be accelerated by irradiation of low dose gamma radiation like as 2 Gy and culture of the callus on M-9 medium in darkness. In suspension culture, shikonin production did not increased in proportion to the growth of cell, and the shikonin was increased by 30 Gy of γ-ray irradiation