What is the pill that says e p 116?

The pill marked "E P 116" is identified as Diphenhydramine hydrochloride 25 mg, which is an over-the-counter antihistamine commonly used to relieve symptoms of allergy, hay fever, and the common cold, such as runny nose, sneezing, and itching. It is also used as a sleep aid due to its sedative properties. Always follow the recommended dosage and consult with a healthcare professional if you have any concerns.