One hundred and sixty cases of mushroom poisoning during the period July-Novemeber 1981 are reported. The survey details 116 observations of short incubation syndromes and 44 cases of delayed syndrome, identified as Amanita phalloides poisoning. Of the latter, 40 patients were adult (mean age 46 years, range 20-77; 18 females and 22 males) and 4 were children (.ltoreq. 12 years old; 3 females and 1 male). All the patients with A. phalloides poisoning were treated according to a therapeutic protocol, based on the infusion of high doses of penicillin G, administration of dexamethasone and thioctic acid, careful correction of water and electrolyte unbalance. The severity of the disease varied in the population of 44 patients: 4 patients died (2 females, 10 and 77 years old; 2 males, 56 and 64 years old); 26 patients were discharged from the hospital as clinically cured; 14 were discharged with persistently abnormal levels of transaminases and they were advised of a follow-up evaluation. The average length of stay in the hospital was 2 weeks. Of the patients followed-up, 6 were symptom-free after 6 months with normal transaminase values and a normal histopathological picture of liver biopsy specimens. In the remaining patients, there was no normalization of transaminase values and liver biopsy specimens showed a picture of chronic active hepatitis. These patients displayed abnormal immunological tests, with presence of immune complexes and of anti-smooth muscle autoantibodies. The results indicate that A. phalloides poisoning represents a threat not only in the high mortality acute phase, but also in the development of chronic active hepatitis in some survivors.