Not really, cough medicines don't really work.
Steam is always good, and keeping the room moist. Sit with him in the bathroom with the shower going for a while, and have bowls of water on the radiator.
Coughs last forever in babies, it's horrible for them 
However, if he is sounding a bit rattly with it, do take him to the GP. <bad mummy>I'm a bit laissez-faire about these things </bad mummy>and left Max coughing for ages once, before finally taking him and he had pneumonia...