Can leftover Chinese herbal medicine be consumed the next day?

Generally, traditional Chinese medicine (TCM) can be reheated and consumed if it has been properly refrigerated and shows no signs of spoilage. However, it should not be consumed if stored improperly or if there are indications of deterioration. If in doubt, it is recommended to consult a healthcare professional in advance. Detailed analysis is as follows:

If the TCM decoction is cooled promptly after preparation, stored in a clean, well-sealed container, and kept refrigerated for less than 24 hours, it is generally safe to consume after being thoroughly reheated to boiling. Before drinking, inspect the liquid for any off-odors, cloudiness, bubbling, or other signs of spoilage. Refrigeration helps inhibit microbial growth and reduces loss of active medicinal components, making this method suitable for individuals who need to prepare their medicine in advance. However, ensure even heating to avoid cold spots.

If the decoction has been left at room temperature for an extended period—especially in hot environments—or if the storage container is unclean or poorly sealed, bacterial growth may occur, leading to souring, foul odor, or formation of flocculent matter. In such cases, the medicine must not be consumed, as it could cause gastrointestinal discomfort such as nausea, vomiting, and diarrhea. Additionally, certain herbal ingredients—such as those containing volatile compounds or animal-derived components—are prone to degradation overnight, and their efficacy may diminish even with proper storage. These types of TCM are best prepared and consumed immediately.

If there is any uncertainty regarding the storage or condition of the TCM—even if there are no obvious visual abnormalities—it is advisable to prepare a fresh batch. Should any adverse reactions occur during treatment, patients should promptly inform their physician.