Overnight lemonade can be drunk if it is properly preserved, but it is not recommended. In general, lemonade overnight, if it is placed in the refrigerator sealed low-temperature preservation, you can still drink. However, after overnight, the nutrients contained in lemonade (such as vitamin C, etc.) are oxidized by the oxygen in the air, making its antioxidant effect greatly reduced. Secondly, the lemon itself contains sugar, the preparation of lemonade will generally add sugar substances and acidity, placed overnight, especially in the summer, it is easy to occur a large number of bacterial reproduction, and then drink lemonade, easy to lead to gastroenteritis and other diseases. Therefore, it is recommended to try to drink fresh lemonade, do not drink overnight lemonade.