The present invention relates to a colloidal anionic oil-in-water emulsioncomprising a prostaglandin, an oil havinga iodine value <；= 2, a surfactant and water, provided the anionic oil-in-water emulsion does not contain polyvinyl alcohol. Thepresent invention also pertains to the use of said anionic oil-in-wateremulsions for enhancing the stability of said prostaglandins,for the treatment of ocular hypertension and/or glaucoma, for promoting growthof eyelashes and/or for treating eyelashhypotri-chosis.
