This invention encompasses novel analogs of Leukotriene B.sub.4 which are selected from a compound of formula I, B--C.apprxeq.C--CH.sub.2 C(M.sub.2)--C.apprxeq.C--Y--C(M.sub.1)--A, or formula II, B--C.apprxeq.C--CH.sub.2 C(M.sub.2)--C.apprxeq.C--P--R.sub.5 --A: wherein Y is: ##STR1## wherein P is: ##STR2## Patentable intermediates, process for making the novel analogs and intermediates and preparation of useful pharmacological agents comprising the analogs and intermediates are part of this invention.