Abstract: 7-[5-oxo-3-hydroxy-2-(3-substituted)-3-hydroxypropyl)-1-cyclopentene]-hepta noic acids having the following general formula ##STR1## wherein X is oxygen or hydroxyl, R.sub.1 and R.sub.3 are independently hydrogen or methyl, and R.sub.2 is --(CH.sub.2)n-Y where n is an integer from 0 through 4 inclusive, and Y is phenyl, or a cycloalkyl group having 4 to 6 carbon atoms. Said acids as well as certain derivatives thereof are useful as nasal decongestants, inhibitors of gastric secretion, inhibitors of platelet aggregation, blood additives, smooth muscle stimulators, hypotensive agents, labor inducers, and in controlling ovulation.