Damp within the house is not to be taken lightly. For a start it can be tricky to diagnose the exact cause, then you need to tackle the root of the problem.
Simply treating the symptoms is only going to mask the issue at best. Dampness is not a problem that should be neglected; it spreads and slowly deteriorates everything it works through.
If your walls are showing signs of moisture or staining, rising damp is the likely culprit. It occurs if water rises up from the ground and travels up through the wall material.