Claire just loved cough mixture. It was very sweet and so, whenever she started catching a cold, she went running to her mother for a dose. And every time she would ask for a bit extra. Her mother often explained to her that you have to take medicine in the correct amounts, but claire wasn't convinced. One night, she had a very strange dream. In it she was minuscule - smaller than a mosquito - and she was living inside a child. She and many others there were responsible for taking some little red balls to the other end of a big bridge. There, some musicians would collect the balls and turn them into musical notes. They were really happy to do this, because when each little ball reached its destination, the conductor of the orchestra added the new note to the tune, continuing the beautiful music which was delighting them all. Before long, they began to run out of little red balls, and for a while the music lost its power and its joy. The child they were living in was becoming sick. Fortunately, the child soon took some cough medicine and the little red balls started appearing again. Likewise, the music became more powerful and joyful, as it had been before. Suddenly, a loud alarm bell went off. The child had taken too much cough mixture! Just then, hundreds of enormous red balls appeared all at once, and they were so heavy that they could hardly move them. A great chaotic commotion began, and the music stopped once more. Claire, with an enormous effort, finally managed to lift one, and she started to walk the bridge. But it was so heavy that the bridge itself collapsed under her feet. And as she was falling, she heard how the music had stopped forever…clair suddenly woke up, with a fright. Thinking about her dream she understood that taking something so good and so tasty like her cough medicine, was a good thing when it was what was needed, but could be very dangerous if you took too much. From then on, she only wanted to take medicine when she really needed it, and whenever she took it she would say to her mother:    -"Just the right amount, ok? I don't want my body filling up with the big red balls." 
A story to explain the importance of taking things in the proper measure, using the example of medicine. 