Loco weed is a term used to describe any of several plants that contain the toxic alkaloid swainsonine. While it may have negative connotations, there are many synonyms for this plant, including locoweed, goofweed, and crazyweed. These names are often used interchangeably to refer to plants that grow primarily in the western regions of North America. Although they may have different names, all of these plants contain toxins that can be harmful or deadly to livestock and humans. As such, it is important to be aware of their presence and to take precautions when handling or consuming them.