The anti-inflammatory properties of topical ocular dimethyl sulfoxide (DMSO) were investigated using a standard experimental model of an acute inflammatory ocular inflammation. Ninety percent and 100% DMSO aggravated the inflammatory response, 50% to 70% DMSO had similar responses as the control eye; however, 30% DMSO had definite anti-inflammatory properties. Dexamethasone 0.1% was superior to 30% DMSO as an anti-inflammatory agent. From this study it is evident that high concentrations of DMSO are irritating to the inflammatory ocular model used while lower concentrations have anti-inflammatory properties. The two side effects of skin irritation at the site of application and breath odor may be the subjective influence that leads certain patients to report a beneficial effect of DMSO treatment in ocular inflammation.