The invention relates to a method and device for checking the blood alcohol level of a driver of a vehicle (V). According to the method of the invention, the driver is provided with an accessory (1) on which an electronic module comprising means for measuring the blood alcohol level by infrared spectrometry and arranged so as to extend while contacting the skin of the driver provided with said accessory, and the vehicle (V) is provided with a central processing unit (9). Further, upon a starting control, the central processing unit (9) transmits a signal requesting the transmission of the measured blood alcohol level, and, when receiving same, the electronic module of the accessory (1) supported on the driver transmits, in return, a signal comprising data representative of the measured blood alcohol level. The central processing unit (9) then triggers a safety procedure when the measured blood alcohol level exceeds a predetermined value.
