Martin Pleasance Tissue Salts Nat Mur Fluid Bal 30ml spray. Nat Mur is the tissue salt responsible for the distribution of water in the body. Symptoms become evident where there is too much water or too little water i.e. where there is dryness. Stomach juices and cell division are made possible because of this salt. Nat Mur can be used with advantage in cases when a salt free diet is recommended. May assist with dehydration, hayfever, watery eyes and-or nose, cold sores, constipation and dry stools, dry and cracked lips, dry eyes and craving salty foods.