Patients with DiHS show an increased risk of sensitization to multiple drugs. We report a case of a young woman who developed cutaneous rash, lymphoadenopathy, malaise and fever after the introduction of phenobarbitale. Because of these symptoms, she was treated with ceftriaxone and she experienced a severe flare-up of the cutaneous and general reaction. Allergological work-up, by cutaneous and lymphocyte transformation test, confirmed a double sensitization to phenobarbital and ceftriaxone. In conclusion, the high risk of DiHS during anticonvulsive therapy should suggest caution in using additional drugs, because of an increased risk of multiple reactions.