antibiotics and plants interaction?

My local aquarium store told me that if I use an antibiotics to deal with a
bacterial infection of the fish that the plants will die.

Is this true?
How long before I can reestablish plants inthe tank?
What do I do to help my fish overcome the infection if i can't use chemicals?

My wholistic approach has been to do a massive water change(i have
excellent water; no cl, nitrates, neutral pH and possibly some Fe) and
subsequently 5-10% changes once a day.  I've added NaCl (1-2TBS per 5 gal)
and 'slime' too.  I'm also concerned that the plants may not tolerate this
level of Cl in the water.

Any suggestions?

thanks ajl