A tissue treatment apparatus and method for treating bone tissue has a controller, an enclosure, a reagent supply system, a draining configuration, and a gas relief valve is controlled by the controller. A bioactive agent may be applied through the reagent supply system. Optionally provided is a gas evacuation assembly, a gas supply unit, a thermal unit for heating or cooling reagents or gases, a sonication unit, any or each operated by the controller. The method provides for programming controller to effect a treatment procedure. In an embodiment of the present application the treatment procedure effects demineralization of the bone material.