A flexible light therapy device, a bandage and a plaster for providing a therapeutic effect to a treatment target area (226) of a living being are provided. The flexible light therapy device comprises a light source (214) for emitting light (220), a light transmitting element (212) and a heat management means (210). The light transmitting element (212) is of a flexible light transmitting material and is optically coupled to the light source (214). The light transmitting element (212) comprises a light exit window (222) to emit the light (220) towards the treatment target area (226). The heat management means (210) is thermally coupled to the treatment target area (226) and distributes heat and controls the distribution of heat across the treatment target area (226). Part of the distributed heat may originate from the light source (214).