Vomiting yellow water in early pregnancy is mainly seen in patients who have a strong early pregnancy reaction and experience more nausea and vomiting. The appearance of yellow water is mainly due to the secretion of bile, which normally enters the intestine through the duodenum to help digestion of food; however, in the case of vomiting, bile will enter the stomach retrograde through the duodenum, causing the yellow substance seen during vomiting, which is the bile of vomiting. Once this happens, it means that the vomiting is more violent and the patient is advised to make sure to take care of rehydration to avoid causing its own acid-base imbalance and also the condition of water loss. Once hyponatremia, hypokalemia, acid-base imbalance, and electrolyte disorders occur, the health of the pregnant woman is again at risk. Therefore, it is important to go to the hospital promptly for symptomatic treatment after these appearances to avoid delaying the condition.