A disposable bag to collect urine and other body liquids that is made from a simple construction and at low cost, allowing a comfortable and secure use, ensuring, after use, the appropriate hermetic sealing, allowing the gelled content inside the bag to assume a regular cylindrical-stem format, facilitating, with the assistance of the metric scale located outside the bag, to establish accurately the correspondence of the volume of liquid lost by the patient, in order that the precise body fluid balance of the patient can be measured.
