Abstract: A cannula is provided for administration of a fluid from two separate sources of supply, such as from an infusion fluid container and an injection syringe, comprising, in combination, a housing, a fluid flow passage therethrough having two fluid inlets and one fluid outlet, one of the fluid inlets being shaped to receive delivery means of an injection device for delivery of fluid to the cannula fluid flow passage, and having a check valve therein compelling flow therethrough only in the inward direction, and means in the one inlet positioned to accept any impact of the delivery means when inserted in the one inlet, and inhibit impact injury to the check valve upon such insertion.