The present invention relates to the delivery of diphenhydramine through an inhalation route. In a composition aspect of the present invention, a composition of a diphenhydramine condensation aerosol is presented. In a method aspect of the present invention, diphenhydramine aerosol is formed by: a) heating a thin layer of diphenhydramine on a solid support to form a vapor; and, b) passing air through the heated vapor to produce aerosol particles having less than 5% degradation product and an aerosol having an MMAD less than 3 microns. In a kit aspect of the present invention, a kit for delivering a condensation aerosol is provided which comprises: a) a thin coating of diphenhydramine; and b) a device for dispensing the diphenhydramine as an aerosol.