water

A woman had some problems, so she went to her doctor of twenty years.
They had the following conversation:
Dr.: Take the red pill after breakfast with one glass of water.
Woman: Ok.
Dr: Take the blue pill after lunch with two glasses of water.
Woman: Ok.
Dr.: Take the yellow pill after dinner with three glasses of water.
After giving these instructions to the woman, she asks, "Can you tell me
what's wrong with me Dr.?
Dr.: Yeah. You do not drink enough water.