Nowadays, in spite of the vaunted progress in medical science, people are still crowding to hospitals, and doctors are busier than ever before. This is partly because of the prevalence of an imaginary illness called hypochondria and partly because of the real stress in modern life. What is needed, therefore, is health of mind, rather than health of body. For this reason I propose a list of 20 do's and 20 don't's, or what to do and what not.