Let's take a minute to talk about your medication. 

This is diphenhydramine. You may hear it called by the brand name 'Benadryl'.  This medicine treats symptoms from allergies or the common cold. For example, it can improve a runny nose, sneezing, watery eyes, or itching of the nose, throat or eyes. Sometimes, diphenhydramine is the active ingredient in sleeping pills. It may have other uses, too.

You should take this medicine as directed on the label, or as directed by your doctor. You should only give it to a child under 6 years old if their doctor tells you to. If you use the liquid form, you should measure each dose with a dosing cup, or a measuring spoon.

Most people feel drowsy after taking a dose. You should wait until you know how it affects you before doing activities that require you to be alert, like driving. You should not drink alcohol. Sometimes, this medicine causes excitability in children. These effects may last for several hours. If these or other side effects worry you, please talk to your doctor or pharmacist.

There are times when you should check with a doctor before using this medicine. Check with a doctor first if you have breathing problems, glaucoma, or an enlarged prostate. Also, check first if you take other medicines that cause drowsiness, such as medicines for sleep, pain, or anxiety. 

For best results with diphenhydramine, follow your doctor's advice for ways to improve your allergy symptoms or sleep habits.