A new computerized barostat allowing digestive tone measurement but also programmed distensions is described. The apparatus consists of a pump, driven by a computer, which injects or aspirates air in a flacid bag placed in a part of the gastrointestinal tract when relaxation or contraction occurs. Several parameters can be programmed for tone measurement: mean pressure, window pressure and air flow rate. Isovolumic or isobaric distensions can be performed using three modes: linear, stepwise or step by step with intermediate deflation. The height (mL or mmHg) of the steps and the duration of the distensions and the deflations can also be programmed. Three automatic and one manual safety systems are included. In comparison with previously described barostats the main feature of this apparatus is that it is entirely computerized and can be used for programmed distensions.