A Big Glass of Water
A man goes to the doctor and tells him that he hasn't been feeling well. The doctor examines him, leaves the room and comes back with three different bottles of pills. The doctor says:

"Take the green pill with a big glass of water when you get up. Take the blue pill with a big glass of water after lunch. Then just before going to bed, take the red pill with another big glass of water."

Startled to be put on so much medicine the man stammers:

"Jeez doc, exactly what's my problem?"

Doctor says,

"You're not drinking enough water."

A little change
The patient shook his doctor's hand in gratitude and said:"Since we are the best of friends, I would not want to insult you by offering payment. But I would like for you to know that I had mentioned you in my will.""That is very kind of you," said the doctor emotionally, and then added, "Can I see that prescription I just gave you? I'd like to make a little change..."