Virechana as a word is taken directly out of the ancient dialectical Ayurvedic books, where it literally means removing the doshas (toxins) out through the rectal route. This is known as purgation. The procedure of purgation helps in ridding your body of (toxic) pitta. Normally, the spot where pitta functions in the body are the intestines. So Virechana involves going through a series of initial preparatory procedures (k/a purvakarma) which serve to extract the pitta (toxic) into your intestines. Then when the receiver of Virechana consumes the remedies for getting the pitta out through the body, he/she is assured to get a full cleansing.
Herbal medicines (purgatives) are used for the purpose of purgation. This guarantees that your body gets the gentle cleansing and does delve into conflict with its nature. According to the types of medicines, purgatives can be bulk-forming, can have lubricant properties or can cause the irritation of the mucosa of the intestine. The bulk-forming medicines like psyllium husk act like fibers (you intake). It absorbs water and makes you purgate your bowels. The oil like castor oil is used as lubricants that help you with purgation. Some drugs like senna irritate your intestine and then cause purgation.
Virechana customarily leads to a state where the toxic and disease-causing Pitta dosha is removed from the body while there is a formation of “new” Pitta and this leads to all the benefits that healthy Pitta has including promotion of digestion and metabolism. Along with this, there are helpful effects of Virechana on common diseases like constipation, unexplained edema, hypertension, acidity and common diseases of skin like psoriasis. Ancient Acharyas described the effect of Virechana as having an all rounding effect on your mind, body and your senses. It promotes intellect, heightens your senses, promotes tissue building, further ignites your digestive fire and is effective for curing diseases.
In some people, there is an absolute contraindication for doing Virechana. When the Pitta in the body is depleted you should not absolutely get Virechana. Folks who are thin, are inebriated, having dry skin, have recently undergone distressing condition of the body, involved in excessive sexual, having ulcers acts should not get Virechana. This might cause what little left of Pitta in your body to be depleted and the positive effect might not be seen. This may rather cause a deleterious effect on your body. It goes without saying pregnant; those with heart disease, stroke, hypertriglyceridemia and conditions where there is an increased chance of bleeding should not go any type of panchakarma procedures.
According to Astanga Hridayam, the time of purgation is after Vamana (emesis), and after 9:00 a.m. (the end of the Kapha time of day). This is done with rapidly acting purgatives. Others suggest medium to mild doses to be taken just before sleep (such that you get purgation before you sleep). The stool is examined to determine the nature of the purgation therapy to be used. Soft stools suggest mild Virechana (e.g., boiled milk, ghee, honey, and cinnamon), while hard stools will require stronger purgative herbs (like triphalá, castor oil, rhubarb, or senna). This too depends on your body type. So if you are Vata you are bound to have slightly constipated bowel and you get stronger purgative, pitta people can easily purgate with mild purgatives such as milk.
The next day (or later that morning), about five stools (movements) are passed, flushing toxins from the small intestine. The number of stools can range from 4 to 15, depending upon the dosha, health condition, etc.
The classical features observed after Virechana are the weakness, fatigue, and feeling of lightness, clarity on thoracic region and clarity of senses. After Virechana, the receiver should follow a strict diet. For few initial days the diet should be semi-solid (mostly gruel) then you gradually build your appetite towards heavier (guru) food. This regimen of diet is known as the paschatkarma. When Virechana is done correctly, your bowel gets clear of toxic pitta, there is a rejuvenation of your bodily fire. This helps your metabolism.
All the procedures of panchakarma should be performed under the proper guidance of an expert Ayurveda practitioner.