A supercritical fluid (SCF) extract of a cardiac glycoside-containing plant mass is provided. The extract can be included in a pharmaceutical composition containing an extract-solubilizing amount of solubilizer. Oleandrin is included within the extract when a cardiac glycoside-containing plant, such as Nerium oleander, is extracted by SCF extraction. The extract can also contain one or more other SCF extractable pharmacologically active agents. The composition can be used to treat a wide range of disorders that are therapeutically responsive to a cardiac glycoside.
