Fluoxetine, also known as Prozac, is a medicine that helps some people feel better when they are sad or upset for a long time. It is like a special kind of medicine called an antidepressant. Just like when you have a cold and your parents give you something to make you feel better, fluoxetine can help people feel better when they are feeling sad or unhappy for a long time. But only doctors can give you this medicine, and they will only do that if they think it will help you.