This is a summary of experiences we have had at The Johns Hopkins Hospital since 1945 in the management of patients with bacterial endocarditis; these experiences are viewed against a background of the observations of others.1-8 Like these others, we are grateful that an infection with a spontaneous recovery rate of only 3% can now be eradicated in some 80% of instances through the proper use of penicillin and other antibiotics. With them, however, we regret that perhaps as many as one-third of these "cured" patients will, nevertheless, ultimately die or be seriously disabled as the result of damage to the heart or other structures induced by the endocardial infection. Together we hopefully await the development of new antibacterial agents which will be effective in instances of penicillin-resistant endocarditis, estimated at some 20% of the total. Clearly, while significant progress has been made in the management of this infection,