If it is overnight water, generally can drink, if it is sugar water or tea, properly preserved when you can drink in moderation, if it has been spoiled usually do not recommend drinking.
Overnight water is the water placed overnight, to determine the overnight water in the end can not drink, need to be based on specific circumstances, can not be generalized. If it is plain water, due to the possibility of contamination is small, so generally can drink overnight plain water. If it is sugar water or tea, if it is properly preserved, placed in the refrigerator, and not contaminated, you can generally drink it in moderation.
However, if the overnight sugar water or tea is not properly preserved, it is more likely to harbor bacteria and deteriorate, and it is not recommended to drink it at this time. Abdominal pain, vomiting and other uncomfortable symptoms may occur easily.
In short, daily life need to pay attention to the management of diet, if you drink overnight water after the discomfort, need to go to the hospital in a timely manner, with the doctor to improve a series of related checks, clear specific causes, so as not to delay treatment.