I might be wrong, but I thought antibioctics didnt work for kennel cough, in the same way they are not good for the common cold. I know when my dogs had it the vet was going to give them antibiotics and some expensive cough medicine. I asked about benilin and also garlic tablets and he reluctantly agreed that this was just as good and I can out nearly £60 better off
Antibiotics are usually prescribed to prevent secondary bacterial infection.
I think a fit, normally healthy dog would recover after a few days without treatment, depending on the particular strain they pick up.
I had a particulary nasty bout a few years ago and my dogs only started to recover once they were all treated with antibiotics.
I now give mine Garlic and Fenugreek as Jane suggested as a prophylactic.
A couple of teaspoons of honey a day is soothing for dogs affected by K.C, set honey is best as runny honey can be a bit messy.
Tracey