A medication infusion device comprises a memory means at a medication reservoir storing data identifying medication in the reservoir, a memory reading means at an infusion pump unit reads data from said memory means, and control means controls an infusion, based on data read by said memory reading means, to start the infusion when the medication is correct. A fluid connection detection means detects fluid connection of the medication reservoir to the infusion pump unit and transmits to control means whether the medication reservoir is connected. The control means controls an infusion in accordance with the transmission from the fluid connection detection means so that when there is no connection between the medication reservoir and infusion pump unit, the infusion pump unit will not be started or, if already started, stopped.