Delirium is the most often encountered psychiatric diagnosis in the general hospital, with incidence up to 85% in the intensive care unit (ICU) setting and with significant consequences on patients' morbidity and mortality. Currently, although not FDA approved, antipsychotics are often considered the first-line pharmacological treatment. However, there can be limitations to their use, including side effects or lack of efficacy. Valproic acid (VPA) is one of the alternatives at times used in such patients which from limited case series data appears to be helpful and tolerated. VPA can provide relief from agitation that poses a threat to the safety and recovery of the patient. Moreover, mechanistically it addresses the neurochemical and cellular abnormalities inherent in delirium (it has NMDA-antagonist, anti-dopaminergic, GABAergic,anti-inflammatory, anti-apoptotic, and histone deacetylase inhibitor properties, among others). The purpose of this study is to evaluate the efficacy and tolerability of the VPA in the first known to us randomized controlled trial.