Folks with stone foundations most likely will deal with water decaying the mortar and even the actual stone. In this case we remove the decayed material and resurface with a mortar mix. This helps maintain the integrity of the foundation. In this situation we also replaced old wood post supports that were splitting.
If you have a stone foundation, as is the case with all foundations, make sure water is flowing away from the structure, you gutters are not clogged and flowing and keep the dampness out of the air with dehumidifier.