D-004 is a lipid extract of royal palm (Rosytonea regia) fruits that prevents prostate hyperplasia induced with testosterone in rodents. Previous studies have shown no D-004-related toxicity in rats, but no study in mice had been reported. D-004 (500, 1000, and 2000 mg/kg) was evaluated in a subchronic (eight weeks) study in NMRI mice. No evidences of treatment-related toxicity were detected. Thus, body-weight gain, clinical observations, food consumption, blood biochemical, hematology, organ-weight ratios, and histopathological findings were similar in control and treated groups. This study supports that D-004 orally administered up to 2000 mg/kg did not induce treatment-related toxicity.