This review focuses on the interactions between nutritional status and drugs in frail elderly persons. Impairment of nutritional status, a component of clinical presentation in the frail elderly, has a major impact on the pharmacology of many drugs devolving from the physiological alterations it generates. Food itself plays a central role in nutritional status and in possible interactions with drugs. Conversely, drugs have often, directly and indirectly, a deleterious effect on the nutritional state of the elderly. However, research in this domain is scarce, and future clinical studies will need to include more elderly and frail elderly individuals, to help clinicians to better understand these interactions.