An implant for releasing an active substance into a vessel through which a body medium flows. The implant release an active substance into a vessel through which a body medium flows downstream from the location of the implant. A base of a biodegradable material is a carrier of the active substance to be released. The body medium flows past the implant and the active substance is release. The implant is configured so that the active substance does not contact a vessel wall at the location of implant.
