Acute bacterial meningitis is an infection of the meninges (the system of membranes which envelops the brain and spinal cord) that often causes hearing loss. Bacterial meningitis is fatal in 5% to 40% of children and 20% to 50% of adults despite treatment with adequate antibiotics. It is caused by bacteria that usually spread from an ear or respiratory infection and is treated with antibiotics. Corticosteroids are drugs that can reduce the inflammation caused by infection. This inflammation has been shown to aggravate damage to the nervous system in experimental meningitis studies in animals. Research on the use of corticosteroids in addition to antibiotics has had conflicting results. This review of 25 trials, including 4121 participants, found that the corticosteroid dexamethasone leads to a reduction in hearing loss and other neurological sequelae in participants in high-income countries who have bacterial meningitis, but is not effective in low-income countries. An analysis for different bacteria causing meningitis showed that patients with meningitis due to Streptococcus pneumoniae (S. pneumoniae) treated with corticosteroids had a lower death rate, while no effect on mortality was seen in patients with Haemophilus influenzae (H. influenzae) and Neisseria meningitidis (N. meningitidis) meningitis. Corticosteroids decreased the rate of hearing loss in children with meningitis due to H. influenzae, but not in children with meningitis due to other bacteria. Dexamethasone increased the rate of recurrent fever but was not associated with other adverse events.