In Japan, a new guideline for toxicology has been published, in which it is recommended to use CT and endoscopy to evaluate the residue in determining the indication for gastrointestinal decontamination. The time from taking the drug, which is indicated for gastrointestinal decontamination, has not been set . The guidelines(Position Statements) on the indications for gastric lavage were published in 1997, and a less-aggressive initial approach has been used for poisoned patients. Clinical studies have shown that the outcomes of retrieval of residual toxic substances in the stomach are variable and that no beneficial effect is obtained. This statement played a role in preventing complications from performing unnecessary gastrointestinal decontamination. However, the presence of residual toxic substances in the stomach before gastric lavage has not been estimated. I would like to give a presentation on the gastrointestinal decontamination described in the new guidelines.