A cute little old lady goes to the doctor and says,

"Doctor I have this problem with gas, but it really doesn't bother me too much. It never smells and is always silent. As a matter of fact I've farted at least 10 times since I've been here in your office. You didn't know I was farting because it doesn't smell and is silent."

The doctor says,

"I see. Take these pills and come back to see me next week".

The next week the lady returns.

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

"Good," the doctor said. "Now that we've cleared up your sinuses, let's work on your hearing."