A penis erection stimulation system comprises an infusion device (11) adapted for implantation inside the patients body and at least one reservoir (R1, R2) adapted for implantation inside the patients body in fluid connection with the infusion device to supply to the infusion device a substance to be injected into the patients body. The reservoir 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 a second substance, said second substance being a drug for stimulating penis erection. The infusion device preferably comprises one or more infusion needles disposed within and implanted along with one or more housings adjacent the patients left and right corpora cavernosa. A pump may be implanted inside the patients body to supply the infusion needle with infusion liquid. A drive unit also adapted for implantation inside the patients 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 patients body for stimulating penis erection.
