Ayurvedic treatment comprises of two parts - Samshodhana and Samshamana. Shamana therapy is a palliative approach that normalizes the vitiated doshas at the seat of aggravation. Shodhana is a purification therapy. The aggravated Doshas from the body are expelled out in this procedure, thereby eliminating the internal causative factors of the disease. Metabolic process causes generation of large quantities of toxic byproducts in the body. Toxins deposited in various tissues vitiate Dosha, Dhatu etc and thereby causes diseases. Shodhana therapy removes toxins from body and restores the equilibrium of Dosha. Shodhana therapy consists of a three-stage purification process as follows:

• Purva Karma – preparatory purification prior to the main purification – Snehana, svedana
• Pradhana Karma – the main five purification methods (known as Panchakarma treatment) – Vaman, Virechana, Asthapana vasti, Anuvasana vasti, Nasya Karma. Some include raktamokshana too.
• Paschat Karma – post purification therapies 

‘Shodhana’ therapy is also called as Panchakarma or five- folds line of treatment.

References 

1. https://herbsandayurveda.wordpress.com/tag/shodhana-chikitsa/
2. Charaka samhita. Chaukhambha sankrit sansthana. Varanasi 221001.
3. Sushruta samhita. Ambika dutta sastri. Chaukhambha vishwabharati prakashana, Varanasi 221001.