The disulfiram-like reaction is linked to the assumption of ethyl alcohol during therapy with the cephalosporin latamoxef, cefamandole and cefoperazone. The reaction is commonly ascribed to the methyl-thiotetrazole group, resembling part of the disulfiram molecule. We describe the case of a patient who experienced on two different occasions a disulfiram-like effect during therapy with cefonicid. This cephalosporin contains the methylsulphothiotetrazole group in place of the methylthiotetrazole group. Our observation is the first related to cefonicid.