Dichloromethane, ethanol, and boiling water extracts of the brown alga Ecklonia cava were examined in vivo for their antipyretic, analgesic, and anti-inflammatory activities in mice. These activities were evaluated by yeast-induced pyrexia, tail-flick test, and phorbol myristate acetate-induced inflammation (edema, erythema, and blood flow). Ethanol extract of E. cava (0.4 mg/ear) inhibited the inflammatory symptoms of mouse ear edema, erythema, and blood flow by 82.6%, 69.0%, and 65.4%, respectively. This extract also demonstrated potent analgesic activity. No acute toxicity was observed after p.o. administration of each extract (5 g/kg bw). These in vivo data are in agreement with the claims of the health care industry and indigenous medicine that E. cava is an effective remedy for inflammation-related symptoms.