A NK.sub.1 antagonist having the formula (I), ##STR00001## wherein Ar.sup.1 and Ar.sup.2 are optionally substituted phenyl or heteroaryl, X.sup.1 is an ether, thio or imino linkage, R.sup.4 and R.sup.5 are not both H or alkyl, and the remaining variables are as defined in the in the specification, useful for treating a number of disorders, including emesis, depression, anxiety and cough. Pharmaceuticals compositions. Methods of treatment and combinations with other agents are also disclosed.