Ok yun, both naman will help you to expel the phlegm hehe inom lang din water it will help to thin/break down yung phlegm

Carbocisteine if u feel like ang kapal and matagal na yung phlegm/ubo mo; Guaifenesin if u feel like chill lang phlegm mo or if pag umuubo ka may something pero hirap ka ilabas, mas heavy duty-ish yung Carbo, tho both works naman.... both take with lots/a full glass of water