EntirelyPets is a privately held online pet supplies company founded in 1999. Based in Union City, California, EntirelyPets sells non prescription pet medications as well as other pet products such as pet toys, pet treats, and cleaning supplies, and ships to all 50 U.S. States as well as internationally.EntirelyPets is a privately held online pet supplies company founded in 1999. Based in Union City, California, EntirelyPets sells non prescription pet medications as well as other pet products such as pet toys, pet treats, and cleaning supplies, and ships to all 50 U.S. States as well as internationally.