Probiotics definitely - BIOCARE do a fantastic one called REPLETE - its expensive but worth it.
Possibly a gel to ease irritation - Natures Sunshine Silver Shield Gel is very good.
Avoid SUGAR like the plague.....possibly wheat and dairy too, but ideally you need to see a Kinesiologist who can test you to see what is right for you. Also kinesiology will treat the cause of why you needed antibiotics in the first place. If you are in the UK go to www.systematic-kinesiology.co.uk to find one near you. My own website gives information about kinesiology www.lindabelcherhealthcare.co.uk