On Dhanteras, Lakshmi - the Goddess of wealth - is worshiped to provide prosperity and well being. It is also the day for celebrating wealth, as the word 'Dhan' literally means wealth and 'Tera' comes from the date 13th. Dhanvantari Triodasi, as it is also called, is the day when Dhanvantari, the lord of medicine appeared. So this is also a day to pray for an ailment-free life. Dhanteras festival also promises health.