The invention relates to a device which comprises a hollow divaricator (17) having a prevalent development direction along a longitudinal axis (Z) and being insertable in a patient's anal orifice. The device further exhibits a window (29) defining an operational area and creating a communication between a cavity (17b) internal of the divaricator (17) and a portion of haemorrhoidal prolapse. The device further comprises means for opening and closing (31) the window (29).