The present paper is intended to provide any physician with a basic information and recommendations on how to behave with individuals who have been irradiated and/or contaminated (or believed to have been exposed), either in the case of a broad nuclear accident or a limited accidental exposure (e.g. occupational). Emphasis is put on the emergency measures to be taken as well as on their relative priority. Information is also provided in order to allow any physician to assess the magnitude and the severity of the exposure on the basis of early clinical symptoms and reactions. This would enable him to sort out the patients and to orientate them towards the appropriate specialized centre, or on the other hand, to reassure the patients. The information and recommendations are presented, purposely, in a concise and schematic way in order to facilitate, when needed, a quick and easy reading.