Probing the natural orifice of the maxillary sinus is the routine practice of some rhinologists, whereas there are many who seldom attempt this method of approach to the antrum. The latter group, representing no doubt a vast majority, usually irrigate the sinus through an artificial opening in the wall of the inferior meatus. The reasons for their preference are: 1. They have difficulty in locating the natural ostium in a large percentage of cases. 2. The sinus cannot be properly flushed out when the return flow is partially blocked by the cannula. 3. Instrumentation of the ostium injures and inflames its membranous lining. 4. The search for the orifice irritates the soft structures of the middle turbinate and the outer nasal wall, producing congestion in the middle meatus, with further blocking of drainage. 5. Spread of infection to the ethmoid labyrinth or even to the orbit is possible,