as human body is considered the most efficient machine.and every machine needs regular cleanings and servicings. So our body needs too.
Panchakarma is the only process for therapeutic cleaning of our body. as the term indicates, Panch-five, Karma- Processes are performed for Samshodhana. 
the process...
Complete panchkarma is devided into three karma(parts)
Poorva-karme: Preparing the body for the panchakarma is poorvakrma.In this process Snehanam & Swedanam are done. Snehana is done internally by taking fat in form of Ghrita and/or tailam (oil)-Vasaa(animal fat)- Majjaa (Bone marrow) and externally by means of oil therapy (massages etc.).Duration is 3 to 7 days. 
swedanam is the done by perspiration/sweating of the body with help of steam etc.
Pradhaan-karma: the main process of panchakarma. five procedures viz. Vaman, virechana, nasya, anuvasana sasthi and aasthaapan basthi are performed as per the requirement.
Vaman-this is for the expulsion of excess kapha.