Diphelin Adult Syrup is indicated for the relief of cough and its congestive symptoms and for the treatment of hay fever and other allergic conditions affecting upper respiratory tract. Active ingredients includes diphenhydramine, sodium citrate and menthol. Diphelin is well absorbed from the gastro-intestinal tract and peak plasma levels are obtained 1 to 4 hours after adminstration by mouth and is excreted mainly in urine as metabolites.