A little old lady farting
A little old lady goes to the doctor and says, "I have this problem with gas, but it really doesn't bother me too much. The farts never smell and are always silent. As a matter of fact, I've farted at least 20 times since I've been here, and I bet you didn't even notice!"
The doctor says, "I see. Take these pills and come back next week."
The next week the lady goes back. "Doctor," she says, "I don't know what the hell 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..."