The antioxidant activities (in vitro) and the lipophilicity (as RM values) of 12 DL-omega-phenyl-amino acid octyl esters with anti-inflammatory/analgesic activities were studied. The tested compounds were found to interact with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH), whereas most of them were essentially inactive in other tests. DL-2-Amino-4-(4-aminophenyl)butyric acid octyl ester was found to be the most active. The anti-inflammatory activity does not seem to be connected with O2-. or HO. scavenging activity at least under the experimental conditions applied. However, the interaction with DPPH was found to be correlated with their anti-inflammatory activity. Between the lipophilicity and the anti-inflammatory activity only a poor relationship exists. For a subgroup of the derivatives of the phenyl glycine octyl ester (1-8) a significant correlation was found between the RM values and the calculated clog P lipophilicity.