What is Amoxicillin prescribed for?

I went to my docs with symptoms of Thrush and was given some canestan duo to clear it up. Had a swab taken and was given 500mg of Amoxicillin... I havent been told why and on reading the internet and the little leaflet inside the box i cant seem to see it saying anywhere that Amoxicillin is used for symptoms of Thrush!! any ideas???