The present invention is directed to pharmaceutical compositions comprising compounds found in Harderian gland secretions, a method of treating dry eye in a human comprising ophthalmically administering an effective amount of a compound, e.g. a lipid compound, found in Harderian gland secretions, pharmaceutical compositions comprising said lipid compounds, as identified by characteristic chemical data and mass spectra of said lipid compounds, said lipid compound in essentially pure form, and an ophthalmic vehicle comprising a therapeutic agent and a compound present in the secretions of the Harderian gland, e.g. a lipid compound, found in the secretions of the Harderian gland, e.g. a rabbit Harderian gland.