Imam Ali (as): Imam Ali (as) said to his son al-Hasan (as), 'O son, shall I teach you four things that will make you needless of medicine?' He said, 'Yes, O Commander of the Faithful.' He said, 'Do not eat food unless you are hungry and get up from eating whilst you still desire to eat more, chew well, and before you sleep go and relieve yourself. If you do these you will be needless of medicine.' Sheikh Ṣadūq, al-Khiṣāl