Sodic Piperacillin was administered to fifteen children with infections including: bronchopneumonia, empyema, cellulitis, osteomyelitis, impetigo, urinary infection, and others. Eighteen bacterial colonies were isolated: 8 staphylococcus aureus, 3 E Coli, 2 proteus mirabilis, 2 S Pyogenes, 1 S pneumoniae, 1 H influenzae and 1 Klebsiella pneumoniae. The dosage was: 117 mg/kg/day, I.V. In 7 cases the therapy was finished via I.M. Clinical cure was obtained in 94% of cases with 70.5% bacterial eradication, 17.6% of persistence and 11.7% not followed post-treatment Pharmacokinetics of the drug was studied. Tolerance to this medication was very good. No important collateral effects were observed.