No simple answer. Some plants are very salt tolerant and can be used in brackish tanks. Some plants hate salt and will rapidly do poorly. However, many plants will survive salt for the period of time for normal medication uses.
So to get a good answer to your question depends upon which plants you have. Tropica used to have a list on their site but I can not find it any more since they "upgraded" the place
I'm having a bit of that problem right now with my two types of hygrophilia. I did a bit of salt after my betta's tail was torn... I've lost a lot of leaves but given a bit of time my plants will recover.