5-S),6-R)-Lipoxin A4 -LXA4) is a trihydroxy fatty acid containing a conjugated tetraene, produced by the metabolism of 15-HETE or 15-HpETE with human leukocytes. 5-S),6-R)-LXA4 is equipotent to leukotriene B4 -LTB4) in inducing superoxide generation in human neutrophils at 0.1 uM. 5-S),6-R)-LXA4 is associated with several other biological functions including leukocyte activation, chemotaxis effects, natural killer cell inhibition, and monocyte migration and adhesion.