Herbal medicine for cough and cold

Di pa man ako buntis i prefer herbal medicine to treat different illnesses,medyo worried lang ako ngayon kung safe kya mgtake ng OREGANO tea simula kasi week 1 ko ngkaroon n ako ng ubo pero hindi nmn grabe. Anyway I'm in my 6th week,1st baby.Sino po may alam kung safe ito? At kung sino yung ng take din during pregnancy.thank you ? God bless everyone