Overnight tea actually has no harm, but tea leaves are prone to oxidation, so teacups often retain tea stains. Additionally, high summer temperatures can lead to bacterial contamination, causing mold or sourness, which may result in diarrhea. Thus, it’s better to avoid drinking overnight tea during this season. Overnight tea, especially if it has developed an off taste, likely harbors large amounts of bacteria, even if the change isn’t immediately noticeable.

Why you shouldn’t drink overnight tea

1. Tea contains polyphenols, which easily oxidize in air and water into brown colloidal substances—tea stains. These stains contain cadmium, lead, iron, arsenic, mercury, and other metals. Tea left overnight or in a cup for too long accumulates more oxidized polyphenols. When ingested, these compounds bind with proteins, fats, and vitamins in food, hindering nutrient absorption.

2. These oxidized substances can also cause inflammation, ulcers, or tissue necrosis in organs like the kidneys, liver, and stomach. Hence, avoid drinking overnight tea and regularly clean tea utensils.

3. In summer, high temperatures accelerate tea spoilage. If left for over 24 hours, it’s best discarded to prevent diarrhea.

4. Overnight tea loses most vitamins, while proteins and sugars become breeding grounds for bacteria and mold, making it unfit for consumption.

Alternative uses of overnight tea

1. Anti-cancer & antioxidant: Over time, tea turns reddish-brown due to polyphenols oxidizing into pigments, both of which have strong anti-cancer and antioxidant properties.

2. Stops bleeding: Rich in acids, overnight tea can inhibit capillary bleeding. Gargling helps with oral inflammation, tongue sores, eczema, or gum bleeding; washing wounds aids healing.

3. Soothes eyes: Its anti-inflammatory polyphenols reduce redness when rinsed over irritated eyes.

4. Relieves itching: Washing hair or skin with warm overnight tea quickly alleviates itching and prevents eczema, thanks to its fluoride content.

5. Promotes hair growth: Washing hair with it reduces dandruff and stimulates growth. Brushing eyebrows daily can thicken them.

6. Strengthens & cleans teeth: Fluoride bonds with enamel, resisting acid erosion and reducing cavities; it also eliminates plaque. Rinsing post-meal is ideal.

7. Freshens breath: Its aromatic oils make it an effective mouthwash to combat bad breath.

8. Soothes sunburn: Applying it with a towel calms sunburnt skin due to its tannic acid and anti-radiation flavonoids.

9. Deodorizes grease: Effectively removes fishy or greasy residues after handling seafood.

10. Aids digestion: Drinking cooled overnight tea in the morning may relieve constipation, boost alertness, and reduce fat.