The synthesis and structure-activity profile of a new class of potent and specific LTA4 hydrolase inhibitors are described. Many compounds of this series of omega-[5-(omega-arylalkyl)-2-thienyl]- and omega-[4-(omega-arylalkyl)phenyl]alkanoic acids were found to be potent in vitro inhibitors of the LTB4 production by porcine leukocytes with IC50 ranging from 1 to 10 microM. The side-chain lengths were