We describe an unusual case of Lactobacillus casei bacteraemia in a heavy dairy consumer woman, with a one month history of low grade fever and admitted to our hospital for sudden onset of severe thoracic pain due to dissection of the aortic arch and ascending aorta. The patient underwent four weeks of intravenous ampicillin (2 g every 4 hours) followed by 2 weeks of oral amoxicillin (1 g every 8 hours) with resolution of fever, thoracic pain and progression of aortic disease. On the basis of the patient's symptoms, a possible penetration of L. casei in an aortic wall defect with development of aortic dissection is hypothesized.