Intraarticular administration of docosahexaenoic acid reduces knee edema in arthritis induced by Complete Freund’s Adjuvant. To determine knee edema, the diameter across the arthritic knee joint was measured and compared to the contralateral knee joint at days 0, 15, 19 and 25 following initial Complete Freund’s Adjuvant (CFA) injection. (A) The intraarticular (i.a.) administration of docosahexaenoic acid (DHA) was performed at days 15, 19 and 22 using doses of 25 μg and 50 μg per mouse injected into the right knee. (B) The i.a. administration of DHA significantly reduced knee edema at doses of 25 μg/joint and 50 μg/joint at days 19 and 25 in CFA-injected mice compared to CFA-injected mice treated with vehicle. Each bar represents the mean ± SEM. *P < 0.05 vs. CFA + vehicle following two-way repeated-measures analysis of variance and post hoc Bonferroni correction.