Effects and Benefits of Overnight Tea

Key Health Benefits:

Cancer prevention, hemostasis (stopping bleeding), elimination of bad breath, and eye protection

Introduction:

"Overnight tea" refers to tea that has been left standing for more than eight hours. During this time, the tea gradually turns reddish-brown—a change primarily caused by oxidation: tea polyphenols in the leaves react with oxygen in the air, generating substantial amounts of tea pigments responsible for the reddish-brown coloration.

Functions and Benefits

1. Cancer Prevention

Overnight tea is rich in tea polyphenols and tea pigments—both potent anticancer compounds. They inhibit the formation of carcinogens within the body and may even help eliminate existing cancer cells. Reportedly, the anticancer efficacy of overnight tea surpasses that of freshly brewed tea.

2. Hemostasis (Stopping Bleeding)

Overnight tea contains abundant tannins, which help prevent capillary bleeding. It can be used as a mouth rinse to treat oral inflammation, glossitis (tongue sores), eczema, and gingival bleeding. Additionally, it may be applied topically to cleanse wounds, abscesses, or skin abrasions with minor bleeding.

3. Elimination of Bad Breath

Overnight tea contains abundant natural essential oils and aromatic compounds. Rinsing the mouth or brushing teeth with overnight tea helps maintain fresh breath and eliminates oral odor, thereby preventing halitosis.

4. Eye Protection

Overnight tea promotes blood circulation and alleviates eye fatigue, helping prevent vision deterioration. Moreover, when eyes are inflamed or exhibit redness (e.g., bloodshot eyes), diluted overnight tea (mixed with warm water) can be used to gently wash the eyes—supporting faster recovery and rapidly relieving symptoms such as eye fatigue, dryness, and irritation.

Precautions

Drinking tea on an empty stomach strongly irritates the gastric mucosa; therefore, consuming cold overnight tea while fasting should be strictly avoided.