Control measures based on careful hospital surveillance are aimed primarily at minimizing environmental sources of Pseudomonas aeruginosa. Other important aspects of epidemiologic control include aggressive evaluation of outbreaks and limitation of antimicrobial use. Potent new antimicrobial chemotherapy has been developed, with most new agents of the beta-lactam and aminoglycoside classes. In spite of these developments, the likelihood of drug resistance seems great and the search for novel compounds continues. Of greatest appeal are approaches that augment host defences. Replacement or supplementation of circulating phagocytic cells is conceptually attractive, but this approach has encountered major technical problems and complications. More recently, there has been important progress in developing immunologic approaches aimed at augmenting circulating antibodies. Development of monoclonal antibodies and new methods for preparing hyperimmune globulins has produced forms of intervention that must be tested by clinical trials, but not all patients may benefit from augmentation of circulating antibodies to P. aeruginosa.