Schuessler Tissue Salt Nat phos is a preparation of Sodium phosphate 6X. The Schuessler Tissue Salts are manufactured by Dr. Reckeweg, a family-owned business whose origins can be traced back to the turn of the century, when the natural physician, Heinrich Reckeweg (1877-1944) founded ' Laboratorium EUPHA' & developed his first complex remedies. They are produced from raw materials of the highest quality & are strictly manufactured in accordance with the German Homeopathic Pharmacopoeia, the European Pharmacopoeia & comply with international production standards.