For when you really really need to sleep, try Vicks ZzzQuil Ultra. This sleep aid helps you fall asleep fast and stay asleep longer. ZzzQuil Ultra tablets contain 25 mg of Doxylamine Succinate. Doxylamine works by blocking the histamine receptors in the brain. This action is responsible for the sedative properties of Doxylamine Succinate. In clinical trials it has been shown to help you fall asleep fast, get less interrupted sleep all through the night, and increase duration of sleep by an average of 27%^ This easy to take sleep aid over-the-counter medicine is non-habit forming for a better, more restful sleep all night.^ All ZzzQuil sleep aids are non-habit forming and specifically formulated with clinically proven ingredients by our team of dedicated scientists. ZzzQuil can be used for occasional sleeplessness when you need a little extra help getting to sleep. ZzzQuil is the World’s #1 Sleep Aid Brand!† ^vs. no sleep aid †Source Euromonitor International Limited; Consumer Health 2022 Edition; Sleep Aids, all channels, retail selling price, Global Brand Name ZzzQuil 2021 data. 24 Tablets