Medicated oil enemas and cleansing enemas comprise basti karma, one of the 5 major karmas or actions performed in Ayurvedic therapeutics. The Rishis extolled basti more than any other treatment, some sages wrote that all diseases can be treated with basti therapy others say 80% and some less. It is really one of the least utilized treatments and if performed properly it can do nothing short of a miracle.

The colon is the last phase of digestion where the ingested substances have been refined to their basic components and thus the maximum absorption happens here of the subtle quality and effects of what we eat. This is performed by a willing army of friendly bacteria that happily co-habit in our gut. Basti when done properly does a number of things:

1. It nourishes and feeds the colonic flora so they may do their job more efficiently thus allowing a higher quality of prana in the system as the last phase of absorption is where the pranic component of the food is absorbed.
2. Improves the immune system by cleansing and nourishing the colon. Modern research has found many key precursor substances are manufactured in the colon.
3. Brings the body into a state of total balance by nourishing the base prana of the body which is formed in the colon (hence it being the seat of vata as per the Ayurvedic texts).

Being the seat of a humor means nothing less than if this organ is functioning properly then that humor will be in balance. When vata is balanced, pitta (metabolism and transformation) and kapha (structure) will be perfectly in balance too. So this explains why basti can perform miracles on many cases in the hands of a skilled physician.

Herewith we have compile references to the greatness of Basti form a variety of texts.

Reference from Astanga sangraha Sutra sthana 28th chapter 3rd shloka.

Basti is the main treatment for wind predominant disorders, because of the instant nourishment without complications and expulsion of the vitiated wind from its root. Wind is the leader for the other doshas and it is responsible for all activities of the body. It is of five types and moves all over body. It is responsible for the creation, maintenance and destruction of internal as well as spiritual entities. It is responsible for all diseases of external, middle and internal roots.  

References from Charaka Samhita

The basti treatment with the proper analysis of strength of the patient and disease, doshas, time, constitution and the drugs selected accordingly cures the particular disease. There is no equivalent for basti treatment because - it does  instant cleaning without any complications, does instant nourishing(तर्पण) or depletion(अपतर्पण), and it does not cause any life threatening complications.(निरत्यय= safe or free from danger or secure).

Here acharya further explains its superiority when compared to virechana treatment. In virechana the katu and teekshna medicines cause discomforts like belchings, nausea and pain in the abdomen where as basti does not cause all these discomforts. Virechana cannot be administered to young and old people as their weak dhaatu bala where as basti can be administered in young and old people also. Basti is the only treatment which gives strength, complexion, happiness to the mind, softness to the body and unctuousness to the body.

Here also acharya explains why basti is important treatment. All shaakhagata and koshtagata, marmagata, urdhwangagata or sarvavayavagata diseases are caused by the wind. Wind is the prime dosha which vitiates stools, urine, pitta, kapha and their asylum. In these conditions no treatment other than basti helps to control wind. Hence aacharyas consider basti as half treatment for any disease and some people consider it as the complete treatment. 

References from Sushruta samhita

Among snehana etc treatments basti is the main treatment because of its many fold benefits. As basti dravya contains many drugs it helps in samshodhana, samshamana and sangrahana of the doshas. Other important functions are it nourishes the weak, depletes the fat, nourishes the eyes, cures premature graying and wrinkles, improves the reduced levels of the shukra dhatu, stabilizes the age, nourishes the body, improves the complexion, strength, health and lifespan.

Wind is the cause for vitiation of the three doshas and highly aggravated wind destructs the body. There is no treatment to   control the wind other than basti like how the seashore breaks down the speed of the waves created by the wind.