The oxidation of the (Z, Z)-1, 4-diene system characteristic of arachidonic acid (Figure 1) is thought to proceed via radical B, itself probably generated by abstraction of an electron from the double bond followed by loss of a proton. This radical B may then add oxygen, a superoxide anion, or superoxide to give C1-3, which may be further reduced to the HETE's. Six of these intermediates can be produced in theory, and five of them have either been ...