Apparatus for detecting the level of alcoholic, chemical or natural products negatively impairing the psychophysical state of a person driving a motor vehicle, of a type comprising: a. at least a detecting sensor to be installed on the motor vehicle and comprising at least two micro-directional fans provided with suitable side deviating fins, capable of collecting the molecules of the drawn substances; said detecting sensor being connected to one or more outer relays enabling the horn, blinkers, headlights, speed limiter, and the detection sensor being connected to the motor vehicle electric circuit and/or the fuel pump to shut off the fuel flow, or the electric circuit outside the control unit, which supplies the current from the battery to the vehicle circuit and to generate consecutive warnings or the vehicle stop; said detecting sensor being capable of constantly analyzing the concentration of alcohol vapours and/or chemical or natural products, and of signalling the results, b. a receiving sensor, such as a central unit or a remote control element, for acquiring and processing the signals from the detecting sensor comprising - anti-intruder control means adapted to short-circuit the system and prevent the vehicle start-up if the inlet opening of the detecting sensor is obstructed; said stop occurs upon the closure of the one or more molecular suction fans; - a fast release device arranged behind the detecting sensor and adapted to release it in case of an acceleration increase caused by an impact of the vehicle; - warning and engine-shut-off means activable in case of a tamper of the connection between the apparatus and its bracket and/or a tamper of the receiving sensor, acting as an anti-theft feature and opening the electric circuit of the motor vehicle and preventing the vehicle from being started up. a. at least a detecting sensor to be installed on the motor vehicle and comprising at least two micro-directional fans provided with suitable side deviating fins, capable of collecting the molecules of the drawn substances; said detecting sensor being connected to one or more outer relays enabling the horn, blinkers, headlights, speed limiter, and the detection sensor being connected to the motor vehicle electric circuit and/or the fuel pump to shut off the fuel flow, or the electric circuit outside the control unit, which supplies the current from the battery to the vehicle circuit and to generate consecutive warnings or the vehicle stop; said detecting sensor being capable of constantly analyzing the concentration of alcohol vapours and/or chemical or natural products, and of signalling the results, b. a receiving sensor, such as a central unit or a remote control element, for acquiring and processing the signals from the detecting sensor comprising - anti-intruder control means adapted to short-circuit the system and prevent the vehicle start-up if the inlet opening of the detecting sensor is obstructed; said stop occurs upon the closure of the one or more molecular suction fans; - a fast release device arranged behind the detecting sensor and adapted to release it in case of an acceleration increase caused by an impact of the vehicle; - warning and engine-shut-off means activable in case of a tamper of the connection between the apparatus and its bracket and/or a tamper of the receiving sensor, acting as an anti-theft feature and opening the electric circuit of the motor vehicle and preventing the vehicle from being started up. - anti-intruder control means adapted to short-circuit the system and prevent the vehicle start-up if the inlet opening of the detecting sensor is obstructed; said stop occurs upon the closure of the one or more molecular suction fans; - a fast release device arranged behind the detecting sensor and adapted to release it in case of an acceleration increase caused by an impact of the vehicle; - warning and engine-shut-off means activable in case of a tamper of the connection between the apparatus and its bracket and/or a tamper of the receiving sensor, acting as an anti-theft feature and opening the electric circuit of the motor vehicle and preventing the vehicle from being started up.