The practice of shankhaprakshalana involves the use of water, salt, asana and ghee. The rules and regulations laid down for the practice are simple and straightforward. They are designed to give maximum results with minimum fuss and potential problems, so that the sadhaka can get on with higher work. It is unfortunate that today many yogic aspirants have lost sight of the essential and simple practice of shankhaprakshalana. They are experimenting with many new variations on the original theme, however, sometimes with unpleasant results. Some groups of people are substituting lemon water, fruit juice, vegetable soup and various herbs, for salty water. Salt has derived a bad reputation, being associated with high blood pressure, and people are afraid to overuse it. The taste of salty water is also undesirable. When we think of just what we are doing in shankhaprakshalana, however, it becomes clear that anything other than mildly saline water taken in such quantities becomes a very intense dose. It is easy to overdo things and injure ourselves.
We have to remember that we must drink two glasses of warm, mildly saline water and perform five asanas eight times each. That is forty movements. This has to be repeated at Least eight to ten times. Therefore this is a potent practice and we must be careful to perform it correctly, so as not to further upset the balance of our system.
Salt is used for shankhaprakshalana because of its reaction in the stomach when it mixes with acids and enzymes. It creates a more dilute and less potent solution. Salt is a very efficient means to dissolve mucus and clean the intestinal linings. In small quantities it has a soothing effect on inflamed linings and also has a mild relationship with the liver. Actually, the amount of salt assimilated in shankhaprakshalana is very small. Very little is absorbed as most of it is excreted via the rectum. Therefore the salt should not create any problem in terms of high blood pressure. People with hypertension, however, should not practice shankhaprakshalana.
Some people prefer the taste of lemon "juice" in their shankhaprakshalana. Certainly, lemon has a good reputation as a cleanser, alkalising agent and container of vitamins. Lemon added to salty water is taken first thing in the morning by many people as a prevention against constipation and disease. It is useful to push a sluggish liver into activity and helpful during colds, flu or seasonal fever. However, these practices use only one or two glasses at the most, and never sixteen to twenty glasses at one time as in shankhaprakshalana. Lemon can be used in laghoo shankhaprakshalana, which is a shorter technique, but never in the long form.
Forty minutes after completing the long form, the aspirant eats a meal of khichari (boiled rice and mung beans with ghee). The purpose of this is to coat the intestines with a protective, soothing and nourishing layer, afforded by the ghee. Without this coating of ghee, the intestinal linings are prey to the corrosive power of acids and alkalis, as well as drying out and cracking, which set the scene for future disease such as ulcers or parasitic infestations.
Salt alone allows the ghee to coat the intestines; lemon will not. Therefore, the use of lemon is prohibited, as is the use of other fruit juices or even vegetable soup. The same thing applies to fasting after the practice. Some people believe that fasting will aid elimination. They are missing the whole point of rebalancing the energies, and in fact debilitate the whole manipura chakra system by straining in this way.
It is for the above reasons that I recommend the full course of shankhaprakshalana be performed in an ashram setting where expert guidance is given and strict controls can be exercised over the saline water, the practice itself and the diet following it. If you attempt this practice outside an ashram, do it under guidance, and remember, follow the guidelines written in the texts very carefully. The ancient yogis, following the instruction of their Gurus, knew what they were talking about from their own experience.