Transcutaneous electrical nerve stimulation, more commonly known as TENS, is widely used in humans and is often well tolerated in dogs and horses. It has beneficial properties to reduce muscle spasms, trigger points and muscle tightness. It is also beneficial for the management of chronic or acute pain caused by injury or a condition. The TENS machine delivers an electrical current via sticky pads called electrodes that are placed on the treatment area. When the machine is on, the impulses pass through the electrodes into the body, causing a contraction. The electrical impulses produced by the TENS machine disrupts the pain signals from the muscle to the brain and causes endorphins to be released, causing an increase in blood flow, which in turn helps to reduce muscle tension and pain.