There seem to be three possible classifications of pernicious vomiting: (1) One of _reflex_ origin, (2) one of _neurotic_ origin, and (3) one due to a _toxemia_, resulting from disturbed metabolism. Not all physicians accept the possibility of all of these factors, however, for while some recognize both toxemia and neuroses as causes, they question the possibility of a reflex cause. Others believe that all nausea of pregnancy, from the mildest to the most severe form, is of toxic origin, while still others contend that even the severest pernicious vomiting is always neurotic. However, as toxicity under any conditions is very likely to give rise to nervous symptoms, and as a nervous, unstable woman may be made very ill by a slight degree of toxicity, it may be that both factors sometimes enter into the causation of this disorder. =Reflex vomiting.= Those who subscribe to the theory of reflex vomiting believe that it may result from the irritation caused by a retroverted uterus, or occasionally by an ovarian cyst, an erosion on the cervix or by adhesions. The treatment for reflex vomiting, quite obviously, consists of correcting the disturbing condition, whatever it may be, after which the nausea usually subsides in a short time. The nurse should take care that her patient resumes a regular diet very gradually, even after the cause of the nausea has been removed, for the stomach has become irritable and the vomiting habit, both mental and physical, though easily established, is usually broken up with considerable difficulty. Breakfast in bed; concentrated liquid foods or easily digested solids, particularly carbohydrates; aerated waters; cold fruit juices and cracked ice are easy to retain and tend to allay nausea. =Neurotic vomiting.= Severe vomiting which is due to some kind of mental stress or suffering, and commonly called “neurotic vomiting,” is not always so easily relieved. In the opinion of many psychiatrists the vomiting frequently constitutes a protection, or possibly a protest, which the patient has developed subconsciously, because of some reason for fearing, or not wanting, to become a mother.