山猫の宇宙

Vomiting is a reflex designed to rid the body of toxic substances in the stomach or to empty the stomach if the body fears it will be too busy doing something important to waste energy on digestion at the moment. If you are in pain you may hyperventilate which causes nausea and vomitting.

确定自己是经痛了、可是我一直没有 这个问题的，
所以 也上网 看看 有关  经痛的医学资料

根据这个资料，经痛往往发生在 没怀孕过的女人身上（其一）。

而造成经痛 甚至 呕吐 的 是一个叫 Prostaglandins 的荷尔蒙：

Prostaglandins are chemicals a woman's body produces that cause many of the symptoms associated with menstrual discomfort. The tissue that lines the uterus makes these chemicals. Prostaglandins stimulate the uterine muscles to contract. Women who have high levels of prostaglandin may experience more intense contractions of their uterus and more pain. Prostaglandins may also be responsible for vomiting, diarrhea, and headaches that accompany painful periods.