Common reversible causes of delirium include urinary retention, constipation, anticholinergic medications, pain, and sleep disruption; these should be addressed when they are found. There is no strong evidence that dehydration causes, or that hydration relieves, delirium. Nonpharmaco­logic measures—including modifying the environment to make it calming and safe, to ensure a clear distinction between day and night, and to frequently reassure and reorient patients to where they are and what is happen­ing—are the cornerstones of delirium treatment. Ramelt­eon, a melatonin agonist, at 8 mg/day orally has been shown to prevent delirium in seriously ill, older, hospital­ized patients. A randomized trial of placebo compared with scheduled risperidone or haloperidol in patients with moderate delirium demonstrated increased delirium and mortality with the neuroleptic. Thus, neuroleptic agents generally should be avoided. However, when agitated delir­ium is severe and poses a significant safety risk or quality of life concern, neuroleptics (eg, quetiapine 12.5–25 mg orally at bedtime or haloperidol 1–2 mg orally, subcutane­ously, intramuscularly, or intravenously every 6 hours as needed) may be used to mildly sedate the patient. Although benzodiazepines can worsen delirium and generally should be avoided, they may be used when deeper sedation is needed to achieve comfort or relieve suffering near the end of life. Such sedation may be achieved with midazolam (0.5–5 mg/h sub­cutaneously or intravenously) or with barbiturates.