Amanita phalloides is the most dangerous, poisonous mushroom species in our climatic conditions. It is the cause of 90-95% of all deaths due to mushroom poisoning, a-Amanitin, a polymerase RNA II inhibitor, is mainly responsible for the Amanita phalloides toxic property. Inhibition of polymerase RNA II functioning in a transcription process is connected with inhibition biosynthesis of structural and enzymatic proteins in cells. A lethal dose of a-amanitin is 0.1 mg/kg b.w. for humans. One of the medical problems in Amanita phalloides poisonings is a relatively prolonged latency period (8-24 h) from mushroom ingestion, at the same time the cytotropic action of absorbed toxins is revealed. In severe cases, multi organ failure, renal and hepatitis failure can occur. Deaths in a-amanitin poising cases follows between 6-16 days after intoxication. Mortality in this group of patients is still high and amounts to approximately 20-30% in adults and exceeds 50% in children. If mushroom poisoning occurs, it is best treated with pharmacological agents, extracorporeal methods for toxin removal and liver transplantation. Recent high expectations concerning liver albumin dialysis (based on MARS) should support liver regeneration and will also help with possible liver transplantation. In a medical community it is generally believed that every suspected Amanita phalloides poisoning should be referred to a specialized health center.