The goal of this study was to investigate the effects of beta-carotene and astaxanthin (ASX) - carotenoid without provitamin A activity on the proliferation and differentiation of rat oval cells (OC) in vitro. Oval cells were isolated from two groups of animals: I - partial hepatectomised (PH) and II- diethylnitrosamine (DEN) treated rats. At various time points cell lysates were separated by PAGE. For immunodetection primary antibodies against CD-34, Ck19 and albumin were used. Medium concentration of fibrinogen and haptoglobin was measured. Mitochondrial competence of cells was expressed as the proliferation index. In comparison to HP- and DEN-obtained oval cells cultured without carotenoids, the addition of beta-carotene and ASX increased albumin expression during the experimental period. The same condition didn't reveal CK19 expression. CD34 expressed by oval cells was detected up to the 5(th) week of beta-carotene and ASX absence in the medium. beta-carotene addition resulted in a decrease of the proliferative activity of OC, with significant changes in 48 h, the 5(th) and 15(th) week of incubation. ASX (p < or = 0.05) inhibited the proliferation, especially in 24h and 5(th) week of cell culture. In respect to haptoglobin concentration, its maximum value after the 10(th) week was observed. The fibrinogen level obtained from DEN-oval cells incubated with beta-carotene elevated from 480+/-6.87 microg/ml after 24h to 5520+/-34,56 microg/ml after the 15(th) week. In a condition without carotenoids fibrinogen concentration did not exceed 2280+/-31.5 microg/ml after the 15(th) week of cell culture.