放屁
在美语里最常用的是 to expel gas 或 to fart 或 to make （或 pass）gas。 例如：
* 医生有时问：「How often do you expel（或 make 或 pass）gas？」（你放屁的次数很多吗？）
* Is the gas expelled by belching？（是否打嗝后就会放屁呢？）（动词是 belch）
* He said the more he ate, the more he farted.（吃的愈多，放屁也愈多。）
* He has passed more gas than usual within the last two days.（过去两天中，他放屁比平常多。）
* Be careful not to fart in the public.（注意在公共场所不可放屁。）
至于消化不良，大便不通或拉肚子，也有不同的说法。 例如：
* I have an upset stomach.（消化不良） = I have heartburn. = I have indigestion.
（注意：Heartburn 是指胃不舒服，不是「心痛」（heartache）
* Something has upset my stomach for two weeks.（胃不舒服有两星期了。）
* He has（persistent）constipation.（或 irregularity）（他经常便秘。) 或
* He has been unusually constipated.（便秘很反常。）或
* He is having problem with irregularity.（或 constipation); 或
* He has no bowel movement for the past few days.
* He has bouts of diarrhea.=He is having trouble with diarrhea.（他拉了一阵肚子。）
* He can see trace of blood and pus or mucus in his stool（或 bowel movement）（大便时可看到血丝和粘膜。）
