Abstract: A percussion vibrator apparatus for treating patients having obstructive pulmonary disorders has a reciprocating member provided with a pad of foam rubber or the like having a 25% compression deflection of from about 5 psi to about 12 psi and a 60% compression deflection of from about 40 psi to about 80 psi. Reciprocating motion is imparted to the member supporting the pad at a high frequency of about 3200 to about 8500 strokes per minute by a drive system comprising a flexible shaft driven by an electric motor and a cam arrangement driven by the flexible shaft and coupled to the pad supporting member. The amplitude of the vibrator is set between 0.0625 and 0.1875 inch for best results.