Thirty-two different cannabinoids were tested for their ability to reduce intraocular pressure (IOP) in the rabbit. These included many of delta 9- and delta 8-THC derivatives and metabolites along with other natural and synthetic cannabinoids. In addition, some non-cannabinoid constituents of Cannabis were screened using the same model. All compounds were administered intravenously, while only a few were tested topically in mineral oil. Water soluble derivatives of delta 9- and delta 8-THC were prepared and tested topically in aqueous solution. The data revealed that certain derivatives of delta 9-and delta 8-THC were more active in lowering IOP than the parent cannabinoids. In addition, compounds other than delta 9- and delta 8-THC and their derivatives were shown to have activity.