The present invention relates to aliphatic compounds of the formula I, or stereoisomers thereof, or their pharmaceutically acceptable salts: ##STR1##

wherein A represents an optionally substituted CH₃C_nH_(2n-2m)— (wherein n denotes an integer of 4 to 22, and m represents an unsaturation number which is an integer of 0 to 7), l represents an integer of 0 to 10, s represents 0 or 1, provided that when s is 0, p+q=4 or 5, but when s is 1, p+q=3 or 4, and in each case, either p or q is an integer of 1 or more, R represents an alkyl group having 1 to 10 carbon atoms which may be straight-chain or branched-chain, and R^A represents hydrogen or an alkyl group having 1 to 10 carbon atoms which may be straight-chain or branched-chain, and their use in suppression of platelet aggregation, in suppression of inflammation, and in prevention and treatment of circulatory diseases.