A 13-week oral repeated dose toxicity study of haematococcus color, a food additive mainly composed of astaxanthin, was conducted in male and female F344 rats. Rats were randomly divided into 4 groups each consisting of 10 males and 10 females and given CRF-1 powder diet containing 0%, 0.025%, 0.075%, and 0.25% haematococcus color, correspond to 0%, 0.5%, 1.5%, and 5% as the product. None of the animals died during the administration period. There were no exposure-related changes in body weight gain or food consumptions. Serum biochemical examinations showed dose-related increase in cholesterol, but the differences were slight and not defined as an adverse effect. No effects related to treatment were noted in hematological examinations and organ weights, and no abnormalities that could be ascribed to exposure to heamatococcus color were observed in histopathological examinations. In conclusion, ingestion of haematococcus color in the diet for 13 weeks does not cause any toxicological changes in F344 rats.