These are one of the funniest kind of jokes because the Medical profession is otherwise a serious profession.
This guy goes to the doctor after being constipated for two weeks.

The doctor prescribes a heavy-duty laxative and tells him to take two when he gets home. The guy goes home to his fourth story apartment, pops two of the pills and lays down for a nap.

When he awakens he finds that the laxative is so powerful that he has relieved two weeks worth of blockage all over the bed as he slept. Totally disgusted the man toils over what to do with the mess and finally decides to bundle up the sheets and pitch them out the window.

About this time a wino comes walking along still hung-over from the night before and splat! The sheet lands Right Square on his head. After struggling for a few minutes the wino gets free of the sheet and as he's standing there looking at it, a policeman strolls up after seeing him wrestling with it.

"What's going on here?" inquires the officer.

"I'm not too sure," replies the wino "but I'm pretty sure I just beat the sh*t out of a ghost!"