Caring for patients involves understanding the ways in which they fulfill their physical natures. Balance in the basic drives of life, such as eating, sleeping, and having sex, is important to the quality of one's life. Imbalance in these fundamental domains, moreover, may reflect an underlying disruption in mental health or, alternatively, threaten mental well-being. Physiological dysfunction accompanying either illness or treatment may further upset this balance, interfering with the regulation of appetite, sleep patterns, or sexual interest and capacities. These dimensions of life are often very private and involve deeply personal concerns for our patients. Impulses, intimacy, image, and insecurities—these are the complex, overdetermined biological and psychological issues that arise. And as with other such sensitive considerations in psychiatric practice, certain values and bioethical principles are held especially dear in caring for these aspects of our patients' lives.