You are probably referring to the ayurvedic terminology of blood purification. While this is probably still practiced in ayurveda, modern allopathic does not advocate that the blood can be purified with an external intervention. The closest procedure that comes close to this is the experimental procedure of liver dialysis. Beyond this, there is no way that the blood can be purified except by the liver in the body.
The liver is one of the most fascinating organs of the human body. It is one of the largest organs and the only one that has the ability to repair itself even if just 25% of it is left in the body, this assuming that the rest of the body systems are in good shape. The liver is responsible for a wide range of activities in the body that include detoxification, playing a role in digestion, hormone production, controlling metabolism, and storage of glycogen after metabolizing fat.
To protect the liver from damage, the best effort that you can do is to maintain a healthy diet and protect the liver from an obvious intake of toxins like alcohol, which is broken down in the liver. One of the greatest dangers to the liver is actually from formulations that claim to purify the blood. These formulations have been discovered to actually be detrimental to liver function and should be avoided. Hepatitis is also something that will impair the liver function and in the long run also causes cirrhosis of the liver, which is the condition wherein a fibrous tissue starts to grow where dead liver cells exist, thereby stopping liver regeneration. Always be sure about your water supply and this can be guaranteed by boiling your water when you are not sure of its purity. The other alternative is to use bottled water. From a dietary perspective, to keep the liver in good condition, tank up on antioxidants. Antioxidants prevent free radicals from roaming freely in the body and causing cellular damage and aging of the body. These are in nearly all leafy green vegetables and in vitamin E. Also, increase your intake of beetroot, cabbage, cauliflower, garlic and onions, honey, and artichoke. All of these have the ability to help the liver absorb toxins and heavy metals as well stimulate bile production and flow, which is important since gallstones are a major reason for surgically removing the gall bladder – the bile storehouse of the liver.