Before generating new compounds, we compiled a dataset of existing compounds tested against COX-2 from the ChEMBL31 database. An initial search revealed 12,155 entries with data on COX-2 activity. After filtering for unique molecules with measured IC50s with no data validity warnings and removing molecules with atoms other than C, N, O, H, S, P, As, Se, or X (halogens), the final set had 3,590 molecules, in the form of SMILES strings. This database will hereafter be referred to as the "ChEMBL31-IC50s" set. Of those, 34 molecules have been approved by some regulatory agency and are referred to as the "approved" set.