Abstract: Described is an endotube for positioning in particular in the esophagus, which at one end has a funnel-like enlargement portion (1), a tubular central portion (2) and at the other end a thickened portion which enlarges towards the central portion and which after having passed through a constriction makes it difficult to withdraw the endotube. The thickened portion is formed from two hollow thin-walled limb portions (3) which are open to the interior of the central portion (2) and which project out of the central portion (2) and which rise in a ramp-like configuration towards the central portion and which then terminate with a steep drop (4). By virtue of that configuration the limbs (3) can be fully folded in, even when an endoscope is introduced into the endotube for positioning thereof, so that the limbs can be easily passed through a constriction. The funnel-like enlargement portion (1) is such that it forms a non-rotatable connection together with an inserted positioning tube.