Racecadoctril is rapidly converted in the body to thiorphan which is a potent enkephalinase inhibitor. Enkephalins are endogenous opioid peptides secreted by myenteric and sub mucosal neurons in the digestive tract. The enkephalins activate the ? opioid receptor, inhibiting the secretion of Cl? and fluids thus reducing the loss of fluids and electrolytes during diarrhea.