Phenergan Liquid is used to treat allergies, insomnia and nausea. __Key Benefits:__ - Treat nausea, insomnia and allergies within 20 minutes - Helps to treat motion sickness - Effects can last up to 12 hours Phenergan Elixir is a treatment that helps to relieve to effects of allergies such as hay fever, pet allergies, dust allergies, and other allergy types. It can also be used as an aid for sleep loss as well as for motion sickness. The active ingredient is promethazine, a first-generation antihistamine. Using promethazine will make you feel sleepy after about 20 minutes. It can sometimes take up to 12 hours for the effects to wear off. If you\'re using Phenergan Elixir for the treatment of a cold, nausea, or allergies it should also start to improve your symptoms within 20 minutes. __Phenergan should only be used for short term uses:__ - Treating adults with insomnia - Treating allergies such as hay fever or rashes - To reduce nauseousness (and travel sickness) The Phenergan Elixir 5mg/5ml Oral Solution is used to block histamine which is produced by the body when you\'re having an allergic reaction. This helps to provide fast relief. Blocking histamine receptors in the part of the brain that controls vomiting can also relieve symptoms of nausea. Phenergan Elixir can also be used to aid people suffering from sleeping problems by working directly on the brain to make you feel relaxed.