The greatest disease is the absence of peace. When the mind is peaceful, your body will be healthy. So everyone who craves for good health must pay attention to their emotions, feelings, and motives that animates them. Just as you wash clothes, you must wash your mind free from dirt every day. To cleanse your mind you should mix in good company and avoid dirt elements like falsehood, injustice, indiscipline, cruelty, hate, etc. Truth, righteousness, peace, love – these form the clean elements. If you inhale the pure air of clean elements, your mind will be free from evil viruses and bacilli, and you will be mentally sturdy and physically strong. As Swami Vivekananda said, you should have nerves of steel and muscles of iron. You must brim in hope and joy as your unshakable resolution, not display despair and dejection.