In my grandmothers house large blue oval pill ## The large oval blue pill marked "MB-111" is identified as Moxatag (775 mg). Moxatag is another brand name for Amoxicillin; which is used to treat bacterial infections caused by susceptible microorganisms. It is usually the drug of choice within the class because it is better absorbed, following oral administration, than other -lactam antibiotics. You can view a detailed description of the drug by clicking on the link below... Please post back if you have any other questions or comments to add.