Disclosed is a composition for forming a temporary obstruction of the intestine of a mammal. The composition is a flowable solution, suspension or dispersion of at least one natural or synthetic polymer and being solidifiable to form a solid plug at a desired site of the intestine and the structure of the plug is changeable for a subsequent, at least partial, removal of the obstruction. The composition contains a thixotropic agent selected from polyethylene glycols and polysaccharides at a concentration sufficient to show thixotropic behaviour.
