Unique natural hot mineral mud forms in the central zone of the hot spring in some places with the hot spring due to prolonged moistening of spring water. The temperature of the mud remains 42 to 60¡æ and the mud contains a large amount of colloidal substances, salts, gases, etc. Applying such hot mineral mud to bury and clean the body generally or locally can stimulate and regulate the nerves and body fluid of the organism. This has anti-inflammatory, pain-checking and cosmetic actions, etc. There are natural or artificial mud bath rooms in places with rich geothermal resources. Bathers soak themselves in the mud of the bathing pool for 3 to 5 minutes or about 10 minutes. Then, they go to the sandy beach to lie down. When the mud on the body dries up in the sun and peels off one lump after another, wash the body clean with clear water. Mud bath has specific therapeutic effects on skin diseases and rheumatic arthritis. For healthy people, it also removes fatigue after they are soaked in the mud pool for a period of time. There existed a kind of mud therapy in the ancient China. However, it was not the hot mud produced by terrestrial heat, but the cold mud dug from the well called "well mud". Medical books in the Tang Dynasty carried this method, such as Qianjin Yaofang, or Valuable Prescriptions and Zhenlei Bencao, or Classified Materia Medica for Emergency. It was used to cure diseases such as threatened abortion due to fetal heat at pregnant stage as well as headache due to wind and heat. This method, in fact, is the so-called humic acidic natrium bath. Besides well mud, the mud in marshland also has the same effects. Humic acid is the substance produced by putrefied organic substances. It has the actions of regulating the endocrine of the organism, inhibiting various harmful enzymes, accelerating blood circulation, promoting metabolism and increasing the immunity of the human body. Mud bath has better therapeutic effects on rheumatoid arthritis, arthralgia of limbs, skin purpura, soft tissue injury of the organism, ulcer of digestive tract, certain obstetrical and gynecological diseases as well as hypertension. It has the therapeutic actions of relieving swelling and restoring physical strength especially in the people with sprain due to competitions or training.
