Sarah, does he have a snotty or congested nose? If so, you can try the nasal spray Physiomer Baby, they have a banner on the main site and are sponsors of BellyBelly until the end of the year. It's like Fess as Cailin mentioned, but unlike Fess, contains no preservative chemicals. Physiomer Baby is completely natural and free of preservative. Check out the banner on the main site

If he just has a cold, there is not much you can do medication wise - some doctors have told me that even medications like Dimetapp often doesn't help. Perhaps you can you give him a little warm water and honey (organic would be ideal) to drink for the throat? Honey is fantastic.