Background <p>Necrotizing fasciitis caused by Actinomyces europaeus is rare, here we report a case of necrotizing fasciitis caused by Actinomyces europaeus infection in a 43-year-old adult male from China. </p> Case presentation <p>A 43-year-old man with inguinal necrotizing fasciitis who initially received clindamycin but showed poor response. Subsequent cultures revealed polymicrobial infection, and therapy was switched to piperacillin-tazobactam with repeated surgical debridement. He was later discharged on oral amoxicillin-clavulanate for three months and fully recovered without recurrence. This case underscores the importance of early recognition, appropriate antimicrobial choice, and aggressive surgical management in Actinomyces europaeus infections. Literature review indicates that treatment duration varies with infection site and tissue vascularity, and β-lactam/β-lactamase inhibitor combinations remain the most effective option.</p> Conclusions <p>European actinomycosis is a rare disease, and the key to treatment is the correct application of antibiotics and effective debridement.</p> Clinical trial <p>Not applicable</p>