The inhibitory activity of 4,4'-dihydroxy-α-truxillic acid and its derivatives (5-1a-5-35a) on nitric oxide (NO) release was evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Compounds 5-3a, 5-4a, 5-5a, 5-10a, 5-24a, 5-26a and 5-30a exhibited significant inhibitory effects on NO production, with IC50 values of 19.8, 21.1, 16.4, 17.5, 20.8, 22.6 and 17.6 μM, respectively. Their cytotoxicities were also estimated using a CCK-8 assay. Among them, compound 5-10a showed no cytotoxic effect on cells up to a concentration of 50 μM. The structure-activity relationships of the compounds are also discussed.