Lactobacilli are commensals in the gastrointestinal and genitourinary tracts and considered as having low pathogenicity. Many species including Lactobacillus rhamnosus are now available as probiotics and their use has widely increased in recent years. Lactobacilli have the propensity to cause invasive infections such as bacteraemia and endocarditis predominantly in an immunocompromised host. We report a case of fatal Lactobacillus rhamnosus endocarditis involving a young patient with a history of complicated cirrhosis and prior Clostridium difficile colitis; and present a literature review and discussion of the possible association of systemic infection with 'probiotic' formulations containing lactobacilli.