The anti-inflammatory effect of a crude fraction of the New Zealand green lipped mussel (Pernacanaliculus) has been investigated. A carrageenan-induced inflammatory oedema of the rat hindfootpad was used as the experimental model. Non-steroidal anti-inflammatory agents were firstshown to be capable of reducing the inflammatory oedema and in the subsequent experiments arepresentative agent was included as a reference substance. The preparation, Perna canaliculus,effectively reduced the footpad oedema but only if injected into the peritoneal cavity. Decreasingamounts were given IP and 500 mg/kg of the crude preparation was found to be the lowest singledose that would produce a significant reduction in the inflammatory response to carrageenan. Lowerdoses were effective if the substance was first administered daily for several days, prior to thechallenge. Oral administration was not effective in reducing the inflammatory response.