Abstract:A 10-litre airlift loop bioreactor was tested for cell suspension culture of Lithospermum eqthrorhizon, the procedure of which was divided in two steps. In the first 14 days, the cells were cultured with modified B5 medium, the cell increment being 4 times as compared with the 2.5 g L-1 of inoculating cells (dwt). In latter 20 days, the cells were cul- tured with modified M9 medium, in which the amount of cells increased again 3.2 times as compared with that at the end of culture in this medium, and 0.6 g of shikonin derivatives per litre of medium can be obtained in a culture cycle. The pH in modified B5growth medium rose with cell increasing in bioreactor. The change in pH of B5 medium had positive relation to the amount of cell growth. On the contrary, pH in M9medium declined with the timeroourse of the formation of shikonin derivatives, which had a negative relation between pH and shikonin formation. It is suggested that the property of cell growth and the formationof shikonin derivatives could be detected by the pH level in the medium of cell suspension cultures in bioreactor.