Background: A New Zealand green-lipped mussel (Perna canaliculus) (NZGLM) is a well-known source of n-3 PUFAs that have been shown to have a high potent anti-inflammatory action. The PCSO-524, the dietary fatty acids supplements, is obtained from the NZGLM by a patented supercritical carbon dioxide (CO2) method. Objectives: To conduct a safety study of the dietary polyunsaturated fatty acids supplement PCSO524® (ANTINOL®) in healthy Beagle dogs and to compare the haematology, blood chemistry and blood coagulation profile of the dogs that received various doses of PCSO-524® (ANTINOL®). Design: A randomized complete blocked design was assigned to forty healthy Beagle dogs (20 males and 20 females) aged between one to three years old, which had body weights between 10 and 15 kilograms. All dogs were separated into four groups, each of which had five males and five females. Adaptation and test periods were of two and eight weeks duration, respectively. Dietary treatments of the current study were basal diet plus 20 empty capsules as placebo, basal diet plus two, six and 20 capsules of ANTINOL. Clinical examination, body weights, CBC and blood chemistry analyses were performed. Duncan’s multiple-range test and a student t-test at a=0.05 were used to used to analyze the for statistic differences. Results: General physical examination did not find abnormalities of the ocular, nervous, musculoskeletal, or integumentary systems during the eight weeks of the safety test. For clinical observations, no sign of illness or behavior change were observed. Parameters that indicated kidney and liver functions appeared to be normal after the administration of ANTINOL supplementation at various doses for eight weeks. Conclusion: The dietary polyunsaturated fatty acids supplement PCSO-524® (ANTINOL®) in healthy Beagle dogs demonstrated no change in feed intake, behavior, CBC and blood chemistry values which suggested that this supplement did not have a harmful effect. Introduction For decades, specific dietary fatty acids supplements, mainly omega 3 polyunsaturated fatty acids (n-3 PUFAs) e.g. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been known for their cardioprotective effect (Adkins & Kelley, 2010), anti-inflammatory effect and immunomodulatory activity (Anderson & Ma, 2009; Fritsche, 2006). As well as fish oils, the New Zealand green-lipped mussel (Perna canaliculus) (NZGLM) is a well-known source of n-3 PUFAs that have been shown to have a more potent anti-inflammatory action than fish oil or drugs (Whitehouse, Macrides, & Kalafatis, 1997). Lipids extracted from the New Zealand green-lipped mussel contain a complex mixture of mainly !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 1!Department of Animal Husbandry, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand, 10330! 2!Department of Pharmacology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand, 10330!