THE SITUATION: Buruli's ulcer is a severe necrotic cutaneous infection due to Mycobacterium ulcerans. It is a major public health problem in developing countries. FROM A CLINICAL POINT OF VIEW: The early stage of the infection corresponds to a painless cutaneous nodule, whereas the late stage corresponds to ulceration with detachment of the edges. There is currently no other treatment than surgical excision combined with heat therapy. FROM A DIAGNOSTIC POINT OF VIEW: Three methods can be used: direct examination of swabs stained according to Ziehl-Neelsen's method, culture in specific medium at 32 degrees C and the polymerization chain reaction assay (PCR). The latter is the technique of choice.