The COX (ovine) Inhibitor Screening Assay directly measures PGF2α produced in the cyclooxygenase reaction. The prostanoid product is quantified via ELISA using a broadly specific antibody that binds to all the major prostaglandin compounds. Thus, this Cayman COX Assay is more accurate and reliable than an assay based on peroxidase inhibition. The Cayman COX (ovine) Inhibitor Screening Assay includes both ovine COX-1 and COX-2 enzymes in order to screen isozyme-specific inhibitors. This assay is an excellent tool which can be used for general inhibitor screening, or to eliminate false positive leads generated by less specific methods.