Unisom is a brand name for over-the-counter medications containing diphenhydramine, which is an antihistamine.

It's primarily used for short-term relief of occasional sleeplessness, also known as insomnia.

Important Note: Unisom can also be used for other purposes, such as:

* Treating allergies (such as hay fever, skin allergies, and the common cold)

* Relieving motion sickness

However, its primary use is for sleep problems.

Always consult your doctor or pharmacist before using Unisom, especially if you have any underlying medical conditions or are taking other medications.