20-trifluoro LTB4 is a synthetic analog of LTB4 resistant to metabolism by ω-oxidation. It is equipotent to LTB4 in chemotactic activity with an EC50 of 3 nM. In contrast to its chemotactic activity, 20-trifluoro LTB4 inhibits LTB4 induced degranulation of neutrophils with an IC50 of 1-2 nM.