What is a small white pill with BL on one side and 130 on the other side?

The small white pill imprinted with "BL" on one side and "130" on the other is identified as Diphenhydramine Hydrochloride 25 mg, a common over-the-counter antihistamine. It is typically used to relieve symptoms of allergy, hay fever, and the common cold, such as sneezing, runny nose, and itching. Additionally, it can be used as a sleep aid due to its sedative properties. Always consult a healthcare professional before using any medication.