C.O.
Ask your doctor. it depends on the medicine- sometimes it's OK, but sometimes it's not. I don't know what the rule is for Augmentin since my baby refused to take it after the first dose. =)
CLARIFICATION (for those who can't believe I would give the advice I did): I was told on one occasion BY THE DOCTOR it was OK to continue antibiotics for an additional 4 days. I was also given the OK to discontinue the Augmentin since it was prescribed as a second attempt to clear an ear infection and his ears had healed in the mean time.
NO ONE SHOULD MAKE MEDICINAL JUDGMENT CALLS ON THEIR OWN. ALWAYS talk to the doctor first and follow their instructions.