Sixty-four severe infections in hospitalized patients were treated with intravenous Timentin. Most patients (mean age: 50.5 years, range 18-85) had serious underlying conditions such as agranulocytosis, heart failure, cancer, diabetes mellitus, chronic alcoholism or other functional or anatomical abnormalities. Forty-three episodes were bacteriologically proved, and bacteraemia was diagnosed in 18. The sites of infection were: lower respiratory tract (10), upper respiratory tract (10), soft tissues (9), urinary tract (7), bones (6), peritoneal cavity (3), meninges (1) and pelvis (1). In addition, 13 episodes of fever and four of septicaemia in patients with agranulocytosis were treated with Timentin plus amikacin. Overall, 59% of the episodes were cured, 14% improved and 17% failed to respond. In 9% of cases the efficacy of the Timentin was unassessable mainly because of concurrent administration of other antimicrobials. Failure appeared to be more frequent in soft tissue and intra-abdominal infections, in patients infected with bacteria susceptible to Timentin but resistant to ticarcillin and in patients superinfected with Timentin-resistant strains. Major side effects were haemorrhagic diathesis with platelet dysfunction (1), severe water sodium overload (1), and possibly pancreatitis (1). Other side effects were mild: catheter-related phlebitis, and abnormal but clinically insignificant laboratory test results. Timentin appears to be an effective and safe broad-spectrum combination which compares favourably with third-generation cephalosporins in the treatment of severe hospital infections. More experience is needed to decide whether the somewhat lower response rate in patients infected with ticarcillin-resistant strains is significant.