Meclizine dihydrochloride is primarily used as an antihistamine to prevent and treat nausea, vomiting, and dizziness caused by motion sickness. It is also effective in managing symptoms associated with vertigo, a condition characterized by a sensation of spinning or imbalance, often linked to inner ear problems. The medication works by blocking histamine receptors in the brain, which helps reduce the signals that trigger these symptoms. It is commonly available in oral tablet form and is typically taken as needed before travel or at the onset of symptoms. Additionally, it is sometimes prescribed for off-label uses, such as alleviating nausea and dizziness in patients undergoing certain medical treatments. Its sedative properties may also provide mild calming effects, though this is not its primary purpose.