I would definitely question your doctor about that. He should only be prescribing it if you have some sort of infection. Antibiotics will kill off the good and bad bacteria, and killing good bacteria could instigate your symptoms.
"but he said I want to see and check something"
Did he say what? It seems as if he's using you as an experiment since you're in remission. Sometimes GIs may prescribe antibiotics (such as Rifaximin) to see if that will help a FLARE, but never while a patient is in remission.
Female, Age 19, Dx w/ UC August 2007
9 Asacol, Rowasa, 1000 mg Canasa, Proctofoam, Rifaximin 2/day
Digestive Advantage (Crohn's & Colitis), 1 Florastor, 50 mg 6MP,1 Primadophilus reuteri, Remicade (3rd infusion 07/08), 2.4 g Lialda, 1 Forvia, 6 Colazal/day