TREAT is a computerized decision support system for antibiotic treatment in inpatients with common bacterial infections. TREAT is based on a state of the art stochastic model of the domain (a causal probabilistic network) and uses a cost benefit model for antibiotic treatment, including costs assigned to future resistance. It was tested in a randomized controlled trial in 3 countries and shown to improve the percentage of appropriate empirical antibiotic treatment while at the same time reduce hospital stay and the use of broad-spectrum antibiotics. The main limitation of TREAT is inherent in the limited information available within hours of presentation.