To investigate the inhibitive effects of different ways of administration of Dexamethasone for fentanyl-cough reflex,two hundred patients scheduled for elective surgery under general anesthesia, were randomly divided into four groups, according to different methods of administration of Dexamethasone.

Effect of preoperative administration of Dextromethorphan on cough reflex during tracheal extubation;

It could also significantly inhibit the coughing response induced by mechanical and electrical stimulations, it was 1/6～1/4.