A little old Asian lady goes to the doctor in China, and says, "Doctor I have this problem with gas, but it doesn't bother me too much... my farts never smell, and they're always quiet. But I've been doing it very often."

The doctor asks her to explain more, and the old lady says, "In fact, I've farted at least 20 times since I've been here in your office. You probably didn't know I was farting because they don't smell and they're silent."

The doctor says, "I see, take these pills and come back to see me next week. "The next week the lady comes back. 

"Doctor," she says, "I don't know what the heck you gave me, but now my farts...although still silent...stink terribly."

The doctor says, "Good!!! Now that we've cleared up your sinuses, let's work on your hearing."