An apparatus and a method for non-invasively decomposing a calculus in a human body include a mechanism for, and the step of, locating the calculus, a mechanism for, and the step of, delivering to the site of the calculus a chemical species known to reduce the calculus, and a mechanism for, and the step of, generating an unfocussed beam of ultrasound radiation for insonating the calculus for enhancing the chemical dissolution of the calculus through the interaction of the calculus, the chemical species and the ultrasound radiation.