A new born baby 3 weeks old is coughing and has a running nose. what can i do? is there any medication i can use?

Nasal wash: At 3 weeks the primary cause of congestion is the environment. House dust, fragrance, perfumes, detergent or cleaning products all leave scents that may not bother you but irritate a babies nose. A good nasal clean out with saline can remove much of this irritant load, but removing the offending irritants from babies life helps more in the long run.Air particle filters can also help.