What kind of pill is a blue oval one that says b 972 on one side and 1 0?

The blue oval pill marked with "B 972" on one side and "1 0" on the other side is identified as Diphenhydramine Hydrochloride 25 mg, which is an antihistamine commonly used to relieve symptoms of allergy, hay fever, and the common cold. It can also be used as a sleep aid due to its sedative properties. Always consult a healthcare professional before taking any medication.