This article analyses the ‘slippery slope’ argument as a means of rejecting euthanasia, outlining its logical, consequentialist structure and four negative consequences commonly cited: the acceptance of involuntary euthanasia, pressure on the patient, the erosion of the doctor-patient relationship, and the weakening of the prohibition on killing. The proposed conclusion is that the argument remains valuable as a complementary element of Christian moral reflection, not as a sufficient ethical basis in itself.