This article examines the psychiatric research and legal doctrine concerning the psychotropic drug prolixin decanoate. Prolixin is a unique drug because, once it is injected into a person, its effects last from two to four weeks. Some courts are now considering the circumstances under which this drug should be forced upon an involuntarily committed individual. The article concludes that because of (a) the shortcomings of psychiatric research on prolixin and (b) the adverse effects of the drug, courts should consider prolixin to be an experimental treatment modality—like psychosurgery—when deciding whether it should be forcibly administered to an involuntarily committed individual.