In this limited series of 23 patients suffering from severe or life-threatening intra-abdominal infection, piperacillin + tazobactam, together with adequate surgical drainage and resections, cured 78% of our patients and eradicated almost all the pathogens. Side effects included essentially eosinophilia and elevation of transaminases but was never severe. Piperacillin + tazobactam seem thus to be an acceptable treatment, associated with correct surgical drainage. This regimen has to be compared in appropriate trial versus gold standard therapy, such as imipenem, a beta-lactam with aminoglucoside and imidazole or clindamycin or with broad spectrum beta-lactam and other inhibitors or beta-lactamases, but our rate of cure is impressive in such a population.