Sylvia Plath is not a self-conscious eco-feminist, but her poems contain rich ideas of eco-feminism, and she, especially, exposes and criticizes the ideology of instrumental reason which is one of the targets of eco-feminism. In her poems she not only portrays the facts that women are demeaned and nature is degraded but also criticizes the colonization logic of dualism and instrumental function of women and nature which mirrors the essence of eco-feminism.