me too. My baby always has "we we"聲 during drink milk. I took him to doctor for 疫苗 and check-up, doctor said his lung is clear, therefore, his lung is ok. He said baby will have less 痰 after 3 months. When we have time, 輕輕拍下痰, 就ok. No need to get 化痰藥. My BB almost day day 嘔痰, but 嘔咗就舒服好多!