The current work examines how cues traditionally used to signal environmental friendliness, specifically the color green and eco-labels, and influence product efficacy perceptions and subsequent purchase intentions. Across three experiments, we find that environmental cues used in isolation (i.e., green color without an environmental label or an environmental label without green color) reduce perceptions of product efficacy. We argue that this efficacy discounting effect occurs because the isolated use of an environmental cue introduces category ambiguity by activating competing functionality and environmentally friendly schemas during evaluation. We discuss the implications of our findings for research on environmental consumption as well as offer insight into the effective use of environmental cues on product packaging.