According to the modified Duke criteria (4), our patient had definite endocarditis. Anaerobic microbes do not commonly cause endocarditis (5) . Most cases of anaerobic endocarditis are caused by anaerobic cocci, Propionibacterium acnes, and Bacteroides fragilis group (5) . We describe the seventh reported case of well-documented infectious endocarditis in which a Veillonella species was the sole pathogen and the first due to V. montpellierensis. Characteristics of the 7 Veillonella endocarditis patients are summarized in the Table. Five of them fulfilled the Duke modified criteria for definite endocardi-tis; the 2 others were possible endocarditis. All previously reported cases of Veillonella endocarditis were due to either V. dispar (9,10), V. parvula (11) , or V. alcalescens (6) (7) (8) , currently considered V. parvula (12) . One patient had no history of fever (7), and 1 patient had no preexisting valvular disease (8) . Five patients had an infected mitral valve; 4 of the 5 had prosthetic valves. Our patient had mitral and aortic endocarditis. All patients had positive blood culture except 2, for whom the diagnosis was made by culturing the valve (6, 11) . Veillonella spp. had also been isolated from intravenous drug users with polymicrobial endocarditis (13); V. parvula was isolated from a lung abscess in a patient with echocardiographic vegetations, but blood cultures were negative (14) . We could not test the susceptibility of the organism because the bacterium was lost on subculture. In treating infections with Veillonella species, penicillin has been the antimicrobial agent of choice (10) . However, recent studies found a notably high resistance to penicillin G (MIC >2µg/mL) (15) . These penicillin G-resistant isolates showed generally reduced susceptibility to ampicillin or amoxicillin but remained susceptible to amoxicillin and clavulanate (15) . We treated our patient for culture-negative endocarditis with amoxicillin. As the clinical state of our patient improved, we did not change antimicrobial agents.