In addition to diagnostic ultrasound, there is also therapeutic ultrasound, a form of thermotherapy. Ultrasound may be used in physical therapy and occupational therapy at higher frequencies because the thermal effects have been found to be helpful for treatment of musculoskeletal injuries, breaking down scar tissue and helping to stretch and warm tendons.

Therapeutic ultrasound may be used to treat many conditions, including osteoarthritis, rheumatoid arthritis, tendinitis, bursitis, fibromyalgia, herniated discs and carpal tunnel syndrome. It can be used to heal wounds such as diabetic foot ulcers and to introduce medication through the skin (phonophoresis).

Unlike diagnostic ultrasound, therapeutic ultrasound has some known risks. The higher frequency of sound may cause damage to a developing fetus and typically will not be used over the abdomen of a pregnant woman. It may also have negative effects on cancerous tissues or areas of bone overgrowth. Patients who cannot perceive pain and heat are also advised against therapeutic ultrasound because overuse can cause burns.