It is elimination of doshas from the body. It is one of the peculiarities of Ayurveda. Since according to Ayurveda, disease is the result of imbalance of doshas, when the increase of dosha is in a large quantity the best way to get cured faster is expelling the doshas out. These procedures (Karmas) are five (Pancha) and hence they are described as Panchakarma i.e. five procedures. These are to be performed not only by the patient for getting them cured but even by healthy persons for maintaining the health. Even this is a pre treatment before rejuvenation (Rasayana) and treatment for virility (vajikarana) also for the best progeny before conception.
It is a lubrication of the body mainly with the use of oil or ghee (clarified butter) . The person is asked to take medicated oil or ghee in increasing quantity till some particular signs and symptoms occur and that much quantity is consumed which takes nearly 12 hours to digest. The person has to be observe some restriction such as drinking only hot water through out the day, no sleep during day time, eating food only when hungry, etc.
Fomentation especially in the form of a steam bath to produce sweating is ‘Swedana‘. This helps liquefaction of doshas so that they can easily tickle down to alimentary canal. Generally this is performed with external snehana.