A frequent complication of totally implantable central venous access devices (TIVADs) is withdrawal occlusion. We describe a case of rare dysfunction of TIVADs: blood withdrawal was possible, whereas infusion was not. A further investigation demonstrated that during infusion, a silicone core, probably produced by hypodermic needle puncture, occluded the reservoir outlet hole. The silicone septum puncture by standard needles instead of non-coring ones may reduce the device effectiveness and expose patients to serious complications.