Lactobacillus species are part of normal gastrointestinal flora and are an uncommon cause of bacteremia. Lactobacillus casei subsp. rhamnosus was repeatedly isolated in the blood cultures of a 43-year-old woman with ulcerative colitis. Lactobacillus spp. could be considered a potential opportunistic pathogen whenever there is disruption of the physiologic architecture of the intestinal mucosa, such as in abdominal surgery, endoscopic procedures, or enteric pathologies. Clinicians and clinical microbiologists need to be aware of this infective complication in patients with ulcerative colitis.