This practice involves cleaning up the nasal passages as well as the throat. It is done with salt mixed water which is called Jala Neti. Water is poured into one nostril and it automatically comes out through the other.
A variation of this is Sutra Neti, where a fine thread is taken inside one nostril and then pulled out of the mouth through the throat. This practice involves passing a specially prepared cotton thread through the nose and out the mouth, back and forth a few times.
There are other Netis also which are done with milk called Dugdha Neti or with ghee/vegetable oil called Ghritha Neti.
Neti is a pre-requisite for cleaning up the respiratory passages for the proper practice of pranayama.
Please do not try Netis without supervision of a trained yogi.
BENEFITS
Neti is the best method of preventing and eliminating colds. Neti is not foolproof, but it goes a long way to solving the problem of colds. A cold indicates something significant, namely that your body is in a weakened condition. If this was not the case, the cold virus would be unable to penetrate the defense mechanism of your body or auto therapeutic powers. The cold virus flourishes in nerve tissue, particularly the olfactory nerves in the nose.
During a cold, Neti greatly helps by removing the accumulated mucus in the nose, this being a breeding ground.
Regular practice of Neti when you don't have a cold keeps the nasal passages working at optimum efficiency and thereby helps to maintain a healthy body. Remember, breathing through the mouth or insufficient treatment of the inhaled air prior to entry into the lungs, due to nasal blockage and congestion, can encourage the onset of disease, by allowing germs to infect the lungs, or by generally weakening the state of health of the body.
Neti is also a help in curing sinusitis, ailments of the eyes, nose and throat, tonsillitis, catarrh, as well as inflammation of the adenoids and mucus membranes.
It is effective in removing headaches, insomnia and tiredness.
Neti has a subtle influence on the various nerves which end in the nasal passages, such as the olfactory bulb and other adjacent nerves which innervate the eyes, ears, etc.
This has a very soothing influence on the brain and can help to relieve such ailments as migraine, epilepsy, depression, tension, etc.
Neti helps in no small manner to prevent and cure lung diseases such as asthma, pneumonia, bronchitis, pulmonary tuberculosis, etc.
Respiration becomes much easier, which leads to an improved intake of oxygen, improved removal of carbon dioxide and consequently better health.