Whole bowel irrigation is a method of gastric decontamination in the poisoned patient involving administration of large volumes of osmotically balanced polyethylene glycol-electrolyte solution to empty the gastrointestinal tract of ingested toxins before absorption, limiting systemic toxicity. While this approach may seem intuitive and it can lead to expulsion of tablets or packets in the rectal effluent, there is a lack of evidence correlating this with improved patient outcomes. Administration of whole bowel irrigation is also challenging to the inexperienced physician and associated with adverse effects, which may be serious. Recommendations for the consideration of whole bowel irrigation are limited to patients who have ingested modified release preparations, those of have ingested pharmaceuticals not adsorbed by activated charcoal, and for the removal of packages in body packers. Until more robust evidence is available from high-quality prospective studies demonstrating efficacy, the use of whole bowel irrigation should not be used routinely in poisoned patients.