The kriyas (also called shatkarmas) are traditional yogic methods for internal body cleansing. They are thought to remove impurities from the system and allow for refreshment, renewal and purification of the body. For more detailed info on these, I'd refer to Asana Pranayama Mudra Bandha by Swami Satyananda Saraswati.
This page is for information purposes only and you attempt any of these practices at your own risk. They should be learned in person from a qualified teacher.
Jala neti (pictured at top) is one of the gentlest kriyas, and is a great way to cleanse the sinuses and prevent the onset of a cold. You'll need a pot that's been specifically designed for this purpose.
Sutra neti (pictured at right) is a more intense type of neti that involves passing a broad thread ("sutra") into one nostril and pulling it out from the back of the throat. It is traditionally done with a waxed length of cord that widens and roughens as it's passed through, but it can also be done with a size 4 rubber catheter.
Trataka or candle-gazing is a concentration-building meditation practice, which soothes mental tension and also cleans the tear ducts. If you wear glasses for nearsightedness, keep them on. Set a steady candle flame at eye level and stare at it, without blinking, until the eyes become tired or tears begin to flow. Relax and repeat 2 or 3 times, and rest your eyes afterward with some palming or sleep. To palm the eyes, rub your hands together rapidly and place the palms over the eye sockets, bringing soothing darkness and warmth without putting pressure on the eyeballs.
Translated as "shining skull breath", this kriya affects the energy body and is said to cleanse the frontal lobe of the brain. It also expels stale gases from the lungs, balances the nervous system, and strengthens the transverse abdominus muscle.
To perform kapalbhati, first find a comfortable meditation posture. Learn to press the lower abdomen (two inches below the navel) towards the spine to create an active exhalation. The exercise is a rhythmic series of these exhalations, each followed by a passive inhalation. The breath is actively "thrown" out with abdominal contractions, and the inhalation happens passively due to gravity and the elasticity of the abdomen.
Ten breath cycles make up one round, and beginners should do 5 rounds or fewer. Experienced practitioners might do 60 to 100 reps in one round. Kapalbhati should be done on an empty stomach, and avoided by individuals with heart disease or hypertension, among other issues.
Vyutkrama Kapalbhati is a less common practice built upon proficiency in jala neti. It involves gently inhaling water through the nose and letting it flow out the mouth. Sheetkrama Kapalbhati is a similar practice that involves filling the mouth with water and exhaling it out of the nose from there. Both of these require drying the nasal canal, as for jala neti.
Uddhyana Bandha shares a name with the stabilization of the lower back and abdomen during standing asana, but is a separate practice done to refresh and stimulate the abdominal organs. It is a.k.a. a stomach vaccuum. To practice it, sit in a comfortable meditation posture. Exhale actively, pressing all the air out, then close the throat at the glottis. Next expand the ribcage, creating a vaccuum that will draw the abdominal organs upward towards the ribcage area. Hold here as long as there is no strain or hunger for air, then release in a controlled fashion.
Agnisar begins with the same exhalation and throat lock, then rhythmically expands and relaxes the ribcage so the abdominal contents smoothly "bounce" up and down.
Nauli is big brother to Uddhyana Bandha and Agnisar, and requires a fine degree of abdominal control. From the uddhyana bandha position, the (rectus) abdominal muscles are contracted first in the centre, then on the left and right, and finally in a rhythmic massaging contraction that moves all around the abdomen. This is best learned from a teacher, but the video below, complete with dance music, is a good introduction.
Basti is a yogic enema that empties the large intestine in a fairly gentle way. It is helpful for both constipation and diarrhea: it counteracts the former, and it helps the latter progress to conclusion more quickly. You'll need a basti kit, pictured at right, to get this one done.
In Vastra Dhauti (pictured at right), a length of cloth is moistened and progressively swallowed. It is then pulled back up, along with a good deal of mucus from the lining of the throat. Success at this kriya requires staying very relaxed as you ever-so-slowly pull the cloth forward. Don't try this one at home, kids.
In Vaman Dhauti (specifically Kunjal Kriya), vomiting is induced by "chugging" clean and lightly salted water until the stomach is overfull, then pushing two fingers to the back of the throat. This is followed by Jala Neti, and is not for the faint of heart or abdomen either.
This practice is a deep intestinal cleanse that requires a few days of attention and care and should be scheduled during some sustained leisure time, under the supervision of an experienced yoga teacher or Ayurvedic doctor.
Laghoo Shankaprakshalana is a shorter, less intense version of the practice that can be done in a morning on an empty stomach. First combine 2L of clean water with 4 tsp of salt. Drink two glasses quickly (yuck!) and then perform the following 5 asanas 8 times each. Page numbers are from the Satyananda Saraswati book mentioned above.
Theis sequence of poses is designed to guide the saltwater through your intestinal tract. It is repeated three times, and may be followed by Kunjal Kriya and Jala Neti. A light breakfast can follow at least a half-hour later.
For the full version, Poorna Shankaprakshalana, you'll need to learn to make ghee. Then learn to make khichari (at right), an easily digestible and balanced meal which is frequently used in ayurvedic treatment of digestive issues.
The practice will empty the intestines and remove much of their mucosal lining. The ghee acts as a temporary substitute for that lining, the rice provides bulk to restore peristalsis and help replenish mucus, and the lentils provide nourishing protein and complete this easily digestible meal. For an academic understanding of this technique, please see the aforementioned book; for an experiential understanding, I'd recommend a stay at a good ashram.
These kriyas have specific therapeutic uses, but are also used by yogic monks and Ayurvedic practitioners as a general tonic for overall health. In my experience, Jala Neti and Basti are the easiest and most practical options; the former helps with colds, and the latter with colonic issues. Again, this page is for information purposes only, and these techniques should be learned in person from a qualified teacher. Happy cleansing, yogis!