In general, functional drinks containing caffeine can provide some refreshing effect. For functional drinks, many nutrients are usually added to the drinks. If they contain caffeine and other ingredients, because caffeine has the effect of stimulating the brain, it can have a certain refreshing effect on the drinker. However, if the functional drinks do not contain caffeine, they generally do not have a refreshing effect. Since the sugar content in functional drinks is usually high, it is generally not recommended to drink a large amount of them to avoid dental caries, obesity, elevated blood sugar and so on. If a large amount of caffeine-containing functional drinks are consumed, it may lead to over-excitement of the central nervous system and affect the quality of sleep. Therefore, it is recommended to minimize the consumption of functional drinks in daily life and pay attention to balanced nutrition and regular work and rest.