The main function of sweating medicine is to release sweat and relieve external heat, expelling cold pathogens from the body through sweating, thereby achieving the goal of treating diseases. Therefore, the best time to use sweating medicine is in the early stages of the disease, when the cold evil has not yet penetrated the body. Sweating can quickly expel the cold evil and alleviate the condition. If you miss this opportunity and wait until the disease has penetrated into your body, using sweat medication for treatment may not be effective, and even lead to body collapse due to excessive sweating.
The main function of administering medicine is to clear the heat and stagnation in the body through purgation, thus achieving the goal of treating diseases. Therefore, the best time to use medication is in the middle and late stages of the disease, when the heat evil has already penetrated the body and needs to be cleared through laxative action. If medication is used too early, it may lead to incomplete elimination of heat and evil, and the purgative effect damages the healthy qi, leading to an aggravation of the condition.
汗药的主要作用是发汗解表，通过发汗来驱逐体内的寒邪，从而达到治疗疾病的目的。因此，使用汗药的最佳时机是在疾病的早期，这时寒邪尚未深入体内，通过发汗可以很快地驱逐寒邪，缓解病情。如果错过了这个时机，等到疾病已经深入体内，再用汗药治疗就可能难以奏效，甚至会因为过度发汗而导致身体虚脱。

下药的主要作用是泻下通便，通过泻下作用来清除体内的热邪和积滞，从而达到治疗疾病的目的。因此，使用下药的最佳时机是在疾病的中后期，这时热邪已经深入体内，需要通过泻下作用来清除。如果过早地使用下药，可能会导致热邪没有被完全清除，而泻下作用又损伤了正气，导致病情加重。