Mixtures of polyethylcne glycols have been used extensively as suppository bases for several years ( 2 ) .These mixtures have desirable characteristics as basessince they do not require refrigeration, provided theincorporated drugs are stable at room temperature.Aspirin is less stable in these polyethylene glycol basesthan in cocoa butter, which has to be refrigerated toprevent melting. The purposc of this study was tostablize aspirin in a polyethylene glycol suppositorybase using additives while retaining the essential characteristics of the base. Of the several additives tested,citric and tartaric acids proved promising. Less effectivesubstances included calcium gluconate, colloidal silica.and acetic acid.