A mixing apparatus for producing a fuel/water mixture for an internal combustion engine includes a fuel line, where via the fuel line a combustion chamber of the internal combustion engine is suppliable with fuel, a connecting region, a water line which opens into the fuel line in the connecting region where via the water line water is introducible via the connecting region into the fuel line and is mixable with the fuel, and a valve arrangement which is disposed on the water line. The valve arrangement prevents an entry of the fuel from the fuel line into the water line when a pressure of the fuel in fuel line is higher than a pressure of the water in the water line.