The present invention is intended to provide a novel agent useful as a therapeutic or prophylactic agent for cachexia, which is a systemic syndrome having major symptoms such as remarkable body weight loss, anemia, edema, anorexia, general prostration, malaise and the like in chronic diseases such as malignant tumor, tuberculosis, diabetes, blood diseases, endocrine disorders, infections, acquired immunodeficiency syndrome, etc. The present invention provides a therapeutic or prophylactic agent for cachexia comprising as an effective ingredient a compound having a specified morphinan skeleton represented by a compound of the following structure: or a pharmacologically acceptable acid addition salt thereof.
