The prompt diagnosis of infective endocarditis is important as the condition is treatable but will almost always prove fatal if left untreated. Should be suspected in febrile patients with a heart murmur on auscultation clinical signs of emboli unknown origin of infection. Diagnosis is based on the clinical picture, a positive blood culture result (in 80–90% of patients with endocarditis), heart auscultation findings and echocardiography (a vegetation and/or valvular regurgitation). Unexplained fever, particularly in patients with a prosthetic heart valve or intravenous drug abusers, should raise the possibility of infective endocarditis. In order to rule out endocarditis, echocardiography is indicated for all patients with septicaemia caused by Staphylococcus aureus or candida, and often for patients with streptococcal or enterococcal septicaemia.