Hepatocyte protection by astaxanthin (100 mg/kg feed for 4 wk with rats) was tested with $CCl_4$ (0.2 mL/100 g weight). The liver catalase and the lipid peroxide contents of the control, $CCl_4$ treated, and $CCl_4$ + astaxanthin treated rats were 17.1, 30.1, and 26.1 mmol/mg protein/min and 1.23, 1.74, and 1.51 ${mu}mol/g$ liver, respectively. These data indicated that astaxanthin attenuated the adverse effect of $CCl_4$. The effect of astaxanthin [300 mg/kg in normal feed for 44 weeks and high-fat feed (10% lard oil, w/w) for the next 26 weeks] on the weight gain was investigated. With the feed of chemically synthesized astaxanthin, the weight increase was significantly slow in the male mice, but not in the females. Chemical astaxanthin decreased the levels of blood glucose, cholesterol, and triglyceride in mice by 4-21%, suggesting astaxanthin can be used to protect hepatocytes and cardiovascular system, and to limit weight gain caused by a high lipid consumption.