A 22-year-old male taking dexamethasone following resection of a medulloblastoma developed an acutely painful swollen knee from which salmonella enteritidis was cultured. He had no gastrointestinal symptoms; one stool culture was positive. Active metalloproteinases without inhibitors were detected in the synovial fluid, a characteristic finding in septic joints. S. enteritidis infecting joints is extremely rare despite being the second most frequent salmonella species after S. typhimurium causing infections in man. The recent findings of S. enteritidis in eggs, and poultry points to one more source of infection. Immunosuppression is likely to facilitate infection.