The acute acalculous cholecystitis (A.A.C.) is a disease with high rates of morbidity and mortality and risk and promoting factors are very important. Pathogenesis has not completely explained, diagnosis is difficult, and there is no agreement on the more effective therapy. The authors present two cases of A.A.C. and one case of not true A.A.C., discuss them and conclude: 1. Parietal ischemia of gallbladder is the most important factor in the pathogenesis. 2. No many diagnostic procedures are necessary if one stress patient's history and clinical findings. 3. The emergency cholecystectomy is the best effective therapeutic procedure and only in selected cases the not invasive procedures are usefull.