Epoxy-fatty acids but not parent fatty acids reduce mechanical pain withdrawal threshold associated with inflammation induced by a single intraplantar injection of 0.5 mg of carrageenan in rat paws (n = 6 per group); data from [49]. The area under the curve (integrated from 0–120 minutes), which gives an overall measurement of the efficacy of a treatment, is reported on the y-axis. Compared to the vehicle control (10% ethanol in saline), the mixture of epoxy-fatty acids significantly reduced the pain (*: p < 0.001). Insert: Individual DHA epoxide (EpDPE: epoxy-docosapentaenoic acid) regioisomers (300 ng /paw) significantly reduced pain (*, p < 0.001, #, p = 0.03, compared to the vehicle). 16, 17-EpDPE and 19,20-EpDPE were similar in efficacy (p = 0.29), while 13,14-EpDPE was more efficacious than them (p < 0.01).