Doxylamine succinate is widely used as an antihistamine to treat symptoms of allergies, such as sneezing, runny nose, and itchy eyes. It is also commonly found in over-the-counter sleep aids due to its sedative properties, helping individuals with occasional insomnia fall asleep faster. Additionally, it is a key ingredient in some medications designed to alleviate symptoms of the common cold, often combined with other active ingredients like decongestants or pain relievers. In some cases, it is prescribed to manage nausea and vomiting during pregnancy, though this use requires medical supervision. Its calming effect on the central nervous system makes it effective for short-term relief of sleep disturbances and mild allergic reactions.