From 1976 through 1984, the period covered in this report, we reviewed our total experience with gram-negative meningitis in adult patients, looking especially at how treatment and mortality had changed. Thirty-nine adults had 45 episodes of gram-negative meningitis. Twenty-five patients had had a dura-arachnoid disruption, 12 a septic episode, and two a bacterial mastoiditis. The overall mortality was 35.9%. Thirteen patients were treated with a full course of intrathecal antibiotics (five or more days) and eight patients with an abbreviated course (one or two doses). The use of chloramphenicol was associated with poor patient outcome, a finding consistent with both experimental and clinical findings of others.