The effects of LiCl on the proliferation of high proliferative potential colony-forming cells (HPP-CFC) and granulocyte macrophage colony-forming unit (CFU-GM) from bone marrow of BALB/c mice were observed. The colonies of HPP-CFC were supported by IL-1, IL-6, WEHI-3 conditioned medium (WEHI-3 CM, which contained IL-3) and L929 conditioned medium (L929-CM, which contained M-CSF); the colonies of CFU-GM were supported by WEHI-3 CM. It was shown that LiCl at concentrations ranging from 0.4 mmol/L to 2 mmol/L significantly inhibited the proliferation of HPP-CFC (P < 0.01), but concentrations ranging from 0.4 mmol/L to 1 mmol/L significantly increased the production of CFU-GM (P < 0.05), both effects displayed in dose-dependent manners. The different effects of LiCl on the proliferation of HPP-CFC and CFU-GM suggest that LiCl may induce HPP-CFC differentiation into more mature cells.