Martin Pleasance Tissue Salts Nat Phos Acid Neut 30ml sp. Nat Phos is the acid neutralising tissue salt and is present in the blood, muscles, nerve and brain cells. It is used in conditions of excess acidity which are characteristically sour smelling. This salt regulates the balance of fats and acids in the body at all times. This tissue salt is known as the alkaliniser and can alleviate arthritic and rheumatic tendencies. Tissue Salts are micro doses of minerals that help rectify mineral imbalances which may be the cause of many common ailments. Tissue Salts may assist the absorption of nutrients from food and supplements.