PROBABILITY-BASED ANTIBIOTIC THERAPY: In children, the risk of an unfavorable course of bacterial infections requires careful selection of the initial antibiotic prescription based on the disease state, bacterial epidemiology and the child's age. ACUTE COMMUNITY ACQUIRED PNEUMONIA: Before the age of 5 years, antibiotics active against Haemophilus influenzae such as amoxicillin or clavulanic acid can be given orally. In children over 5, amoxicillin or a macrolide are effective. SEVERE EAR, NOSE AND THROAT INFECTIONS: For sore throats, clinical and bacterial results of a 4-day antibiotic regimen using a second generation cephalosporin are equivalent (with better compliance) to a 10-day regimen of penicillin V. For acute middle ear infections, a combination of amoxicillin-clavulanic acid is usually prescribed as initial treatment. COMMUNITY ACQUIRED BACTERIAL MENINGITIS: The most recent consensus established the indication for cefotaxime or ceftriaxone. The increasing number of peni-R pneumococci and the major drop in the frequency of Haemophilus infections have led to new therapeutic propositions currently under investigation. ACUTE SKIN INFECTIONS: For impetigo, general antibiotics-oxacillin or a derivative-are required due to the risk of contagion. BONE AND JOINT INFECTIONS: For these urgent situations, in vitro sensitivity and antibiotic penetration into the infected tissue are the determining factors. BACTERIAL DIARRHEA: Antibiotics are not required in case of acute diaarhea with little or no fever. Antibiotics could be discussed for cholera-like diarrhea and are required in case of invasive bacterial diarrhea, shigelosis, cholera, and Clostridium difficile as well as diarrhea with fever and blood loss in infants or salmonella-induced diarrhea with signs of extradigestive complications. URINARY TRACT INFECTIONS: The choice of the antibiotic and the duration of treatment depend on the clinical presentation: lower tract infection, acute pyeloephritis, or prophylaxis. The causal germ must be identified for adapted antibiotic treatment.