What kind of pill is yellow and blank on both sides... no letters or markings?

Hi! This is from the Pill Identifier:
"All prescription and over-the-counter (OTC) drugs in the U.S. are required by the FDA to have an imprint code. If your pill has no imprint it could be a vitamin, diet, herbal, or energy pill, or an illicit or foreign drug. It is not possible to accurately identify a pill online without an imprint code."

I'm sorry I couldn't be of more help. You might try ask a pharmacist if it's anything they recognize.