Intraarticular administration of docosahexaenoic acid reduces pain-related behaviors in arthritis induced by Complete Freund’s Adjuvant. Docosahexaenoic acid (DHA) or vehicle was intraarticularly (i.a.) administered at days 15, 19 and 22 after initial Complete Freund’s Adjuvant (CFA) injection into the right knee at doses of 25 μg/joint and 50 μg/joint. (A) Behavioral analysis was performed at days 0 and 15 (immediately prior to i.a. administration of DHA) and at days 19 and 25 following initial CFA injection. (B) The two doses of DHA significantly reduced the number of spontaneous flinches. (C) The horizontal exploratory activity increased significantly in CFA-injected mice following DHA treatment. (D) The i.a. administration of DHA did not significantly increase the number of vertical rearings as compared to CFA-injected mice treated with vehicle. Each bar represents the mean ± SEM. *P < 0.05 vs. i.a. CFA + i.a. vehicle according to its respective time by two-way repeated-measures analysis of variance followed by post hoc Bonferroni correction.