Marked changes in physical appearance manifested by dry formulations containing aspirin, an antihistamine, and vitamin C during an accelerated temperature stability study are discussed. The stabilization afforded by a resin adsorbate of a commonly used antihistamine, pyrilamine, is noted. Discrepancies in the results obtained from stability studies of these preparations have been traced to the efficiency of the closure utilized in the packaging of the product, as well as the methods employed in the pretreatment, sampling, and evaluation of test samples. The implications of these observations from a developmental standpoint are discussed.