It would depend on the cause of the dampness. I wouldn't think that it would help the most common causes of dampness.

1. Rising Damp.
which is usually dealt with by the installation of a damp course.
2. Seepage into a basement.
3. Outside ground higher than the ground floor.
These last two can be cured by a combination of tanking and landscaping.

Some electrolytic systems are also available which can be retrofitted to an old house.