A penis erection stimulation system comprises an infusion device (11) adapted for implantation inside the patient's body, at least one reservoir (R1, R2) adapted for implantation inside the patient's body in fluid connection with the infusion device to supply to the infusion device a substance to be injected into the patient's body, and a cooling device implantable along with the reservoir for keeping the content within at least one compartment of the reservoir at a temperature below 37° C. The reservoir preferably comprises at least one first compartment accommodating or adapted to accommodate a first substance and at least one second compartment accommodating or adapted to accommodate as a second substance a drug for stimulating penis erection, wherein the at least one second compartment is cooled by means of the cooling device. The infusion device preferably comprises one or more infusion needles disposed within and implanted along with one or more housings adjacent the patient's left and right corpora cavernosa. A pump may be implanted inside the patient's body to supply the infusion needle with infusion liquid. A drive unit also adapted for implantation inside the patient's body may be arranged for advancing and retracting the tip end of the infusion needle such that it penetrates the housing at least in two different penetration areas either simultaneously or in immediate time succession, thereby injecting drugs along with the infusion liquid into the patient's body for stimulating penis erection.
