MODEL RELEASED. Mud bath. Women in a thermal mud bath at a rheumatism clinic. Rheumatism is a group of conditions that are characterised by painful joints and muscles. Mud baths are a form of hydrotherapy, the application of water for therapeutic purposes. The mud in a mud bath is ideally rich in minerals and vitamins, and may even contain antibiotics. The mud also has an abrasive effect, which helps to clean the skin. The heat and nutrients in a thermal mud bath soothe joints and improve blood circulation, and give the skin a fresher, more healthy look.