1. 1. Total analysis time is short. 2. 2. Reproducibility is ± 0.5 min using the same column over a 3-month period for the primary prostaglandins. 3. 3. The HPLC system is generally applicable to the analysis of all PG synthase and most lipoxygenase products and ensures optimization of the method for analysis of arachidonic acid metabolites. 4. 4. The design, in the step isocratic mode, allows the utilization of a single pump with a three-way solvent selecting valve for the separation of these metabolites. This will significantly reduce the capital costs of acquiring such a system.