Gastric lavage is now known to be ineffective, unnecessary or hazardous in some circumstances where it used to be performed as a routine. This article concerns the medico-legal aspect of forced gastric lavage. The Supreme Court 2005.1.28, 2003da14119 is the case where a patient, who ingested the organophosphate insecticide to attempt suicide and refused lavage. At first we discuss the effectiveness or hazards of lavage because a very high degree of proof -of negligence, not error of clinical judgment - would be required. Lavage, with or without the informed consent, performed negligently which result in harm could, of course, give rise to a claim in negligence. A doctor might also be held negligent in failing to perform an act which he/she had a duty to perform.