Necrotizing fasciitis continues to occur due to beta-haemolytic streptococci but is now also recognized as being due to Vibrio spp. in fishermen and those in contact with warm water in the Gulf of Mexico and South-East Asia, including Hong Kong. Magnetic resonance image scanning has identified the extent of fasciitis and soft tissue oedema infiltrating fascial planes prior to necrosis presenting clinically and is a useful tool in early diagnosis. Surgical debridement or incisional drainage remains essential. An enhanced bactericidal response against beta-haemolytic streptococci has been found with a combination of penicillin and clindamycin. Intravenous immunoglobulin has been shown to reduce mortality if the necrotizing fasciitis is associated with the toxic shock syndrome, by decreasing the superantigen activity of the beta-haemolytic streptococci on cytokine release by T cells.