胃酸，在胃内消化食物，

但是：如果反流至食管，可导致：

                                              反流性食管炎

                                                          Barrett’食管

                                                          食管狭窄

                                                          食管腺癌

如果反流至气管，可导致： 

                                                           支气管哮喘

                                                           慢性支气管炎

                                                           慢性肺炎

                                                           肺气肿

如果反流至咽喉，可导致： 

                                                           慢性咽炎

                                                           慢性喉炎

                                                           睡眠呼吸暂停综合征

如果反流至口腔，可导致： 

                                                           龋齿

                                                           口腔溃疡

                                                           牙齿块状脱落

                                                           中耳炎