Shunt infections occur in 6–25% of hydrocephalic patients with shunts. Although Staphylococcus epidermidis and Staphylococcus aureus cause the majority of such infections, enteric bacteria account for at least 10–15%. The clinical presentation in most patients is nonspecific. Most investigators agree that the entire infected shunt should be removed before antibiotic therapy is initiated. The choice of an antibiotic should be guided by in vitro susceptibility of the etiologic agent, and the ability of the drug to pass the blood-brain barrier. The efficacy of prophylactic antibiotics in reducing shunt infections is controversial.