What pill is a capsule that is green with a white stripe and the letter L and the number 1?

The capsule you described, which is green with a white stripe and marked with the letter "L" and the number "1," is identified as Diphenhydramine Hydrochloride 25 mg. Diphenhydramine is an antihistamine commonly used to relieve symptoms of allergy, hay fever, and the common cold, as well as to treat insomnia and motion sickness. Always consult a healthcare professional for proper usage and advice regarding medication.