Light-based systems and methods are provided with targeted antibacterial action for mouth care in animals such as dogs. In various embodiments, the device includes a substantially impermeable shell. The shell has an outer surface. The outer surface has at least one substantially transparent region. The device further includes at least one light-emitting diode disposed within the shell. The at least one light-emitting diode is adapted to emit light having a wavelength between about 400 nm and about 1,000 nm when powered. The at least one light-emitting diode is configured to provide an average light intensity of between about 10 and about 50 mW/cm2 across the at least one substantially transparent region of the outer surface. The device further includes a power source disposed within the shell. The device further includes a switch at least partially disposed within the shell and adapted to control current flow from the power source to the at least one light-emitting diode.