In contrast to chemotherapy and surgery, physiotherapy is a method that uses physical factors to act on the body to treat or prevent disease, also known as physical factor therapy. There are many kinds of physical factors, such as those that exist in nature, such as sunlight, air, seawater, beaches, hot springs, etc., and those that are artificially created, such as electric current, light, laser, ultrasound, electromagnetic waves, etc. There are many kinds of physical therapy and they are widely used, such as warm water baths, medicinal baths, sun baths, hot spring baths, beach baths, low-frequency, medium-frequency or high-frequency electrotherapy using electric current, infrared and ultraviolet radiation or microwave physical therapy, manual massage and so on.