Inclusion Criteria: - Adult patients (aged over 18) - Symptomatic CSDH confirmed on cranial imaging - Informed consent from patient, next of kin or IHP. | - Patients with conditions where steroids are clearly contra-indicated - Patients who are on (or within 1 month of) regular oral or intravenous corticosteroids. - Previous enrolment in this trial for a prior episode - Time interval from admission to neurosurgical unit to first dose of trial medication exceeds 72hrs. - CSDH in presence of a cerebrospinal fluid (CSF) shunt - Severe lactose intolerance or any known hypersensitivity to dexamethasone or any investigational medicinal product (IMP) excipients - Patients with a previous history of psychotic disorders - Unwillingness to take products containing gelatin - Concurrent enrolment in any other trial of an IMP |