The cochlea is a sensitive, highly metabolically active, and fragile organ that is easily, adversely affected by injury, leading to sensorineural hearing loss. The challenges may be noise, infection, or the attrition of hearing due to age (i.e., presbyacusis), but there are also several drugs that can instigate ototoxicity, causing cochlear dysfunction and resulting in hearing loss and tinnitus. Many of these drugs, particularly those that are strongly ototoxic, are only prescribed in cases of extreme need, such as chemotherapy for cancer, or severe infection, although others that have a less common or strong effect are in use for less life-threatening/limiting conditions such as arthritic pain and muscle cramp. This entry reviews the most commonly used ototoxic drugs and details the known mechanisms, impact, and ...