Drinking cold water is not harmful to the human body. In fact, it can be beneficial in certain situations, such as after exercising, as it can help to replenish fluid levels and reduce body temperature. However, drinking extremely cold water can be uncomfortable and may cause digestive problems for some people, especially if consumed too quickly. It's also important to note that drinking water that is contaminated with harmful substances, such as bacteria or chemicals, can be harmful to health regardless of the temperature. In general, it's recommended to drink water that is at a comfortable temperature and to make sure it's from a safe and clean source.