An apparatus for treating oedema of members of the body, comprising a vertical cylindrical vessel, a flexible tubular outer bag located in the vessel and having a closed end and an opposite opened end, means for fixing a periphery of said open end to a periphery of an upper part of the vessel, an inner flexible bag having a closed end and disposed coaxially inside the outer bag, the bags defining therebetween a small closed space, and means for introducing a liquid of high density in said space, and means for achieving in the vessel and around the outer bag a solid molding, which is capable of being disaggregated, of a member of any size introduced in the inner bag.