The invention is directed to a method of administering pharmaceutical compositions comprising peptide drugs such as a calcitonin in combination with one or more oral delivery agents, together with an amount of a liquid, and method of treatment of disorders responsive to the action of peptide drugs such as a calcitonin employing such method of administration so as to enhance the oral bioavailability of a calcitonin. The methods of the invention increase the oral absorption and systemic bioavailability of peptide drugs, such as a calcitonin.