The diagnosis of infective endocarditis can be difficult, particularly with atypical presentation and negative blood cultures. A 61-year-old man with a porcine aortic valve presented with fever, intermittent confusion, diarrhea, and fatigue. In the community clinic setting, a colonoscopy performed for anemia demonstrated colitis. Symptoms progressed for months; elicitation of a history of significant kitten exposure and the finding of an axillary lymph node prompted testing for Bartonella henselae antibodies. High titer antibodies by indirect immunofluorescence assay indicated chronic B. henselae infection. Surgical valve replacement followed by prolonged doxycycline and rifampin led to cure. This case illustrates the complexities of infective endocarditis and is the first description B. henselae endocarditis associated with colitis in an immunocompetent adult.