Abstract: Automatic regulation system of a flow of liquid, which system comprises an electronic liquid flow control circuit connected to a liquid flow regulation device which it actuates, the said electronic circuit being characterized in that it comprises a drop counting circuit connected to a comparator circuit which comprises a bistable circuit which is itself connected on the one hand to alarm circuits and on the other hand to a monostable circuit, the magnitude of the pulse of which is compared with the magnitude of the pulse of the bistable circuit by means of a comparator circuit to which the bistable and monostable circuits are connected. Said system is used for automatic regulation of the flow of a perfusion liquid.