That phenoxymethyl penicillin (penicillin V) could be successfully employed in the treatment of subacute bacterial endocarditis was first demonstrated by Quinn and his associates, in 1956. 1,2 Some of their patients were treated with phenoxymethyl penicillin alone and some with this antibiotic in conjunction with intramuscular streptomycin. The following year Walker and Hamburger 3 reported four cases of subacute bacterial endocarditis caused by penicillin-sensitive streptococci successfully treated with two weeks therapy of oral phenoxymethyl penicillin and intramuscular streptomycin. As far as we know, however, no cases of Streptococcus faecalis endocarditis treated with oral penicillin have yet been reported. According to Hunter, 4 the acceptable form of therapy of S. faecalis endocarditis is a combination of 10,000,000 to 15,000,000 units of penicillin G per day, plus streptomycin. The first patient presented here was given only 1,000,000 to 2,000,000 units of penicillin per day parenterally, with the major portion of the penicillin