Can i use brewers yeast and antibiotics (along with flagyl for the yeast infections caused by antibiotics ) all together? is it fine if i take them everyday separately?

Confusing question. Yeast infection is not treated with metronidazole (Flagyl). Your doctor is treating you for something other than yeast (unless you have both yeast and a bacterial infection or trichomonas). Are you taking anti-yeast treatments like a vaginal azole cream or fluconazole (Diflucan) by mouth? Brewers yeast is not effective against any infection, but it won't cause any harm.