However, not everyone is suitable for drinking tea for health preservation. Let's take a look at which conditions require us to stay away from tea leaves.

Patients with liver disease should avoid drinking tea.

Most substances in tea, such as caffeine, are metabolized by the liver. If the liver is diseased, drinking excessive tea beyond the liver's metabolic capacity can damage liver tissue.

Those with neurasthenia should drink tea cautiously.

The caffeine in tea stimulates the central nervous system. Drinking strong tea, especially in the afternoon and evening, can cause insomnia and worsen the condition for those with neurasthenia. They can drink tea once in the morning and once in the afternoon. In the morning, flower tea is suitable, and in the afternoon, green tea is recommended, but avoid tea in the evening. This way, patients can feel energized during the day and calm at night, helping them fall asleep earlier.

Patients with ulcers should drink tea cautiously.

Tea is a stimulant for gastric acid secretion. Drinking tea can increase gastric acid secretion, irritating the ulcer surface. Regularly drinking strong tea can worsen the condition. However, for mild cases, drinking some weak tea two hours after taking medication may be acceptable. Adding sugar to black tea or milk to black tea can help reduce inflammation and protect the gastric mucosa, potentially benefiting ulcers. Drinking tea can also block the synthesis of nitrosamine compounds in the body, preventing precancerous mutations.

Patients with coronary heart disease should drink tea cautiously.

For coronary heart disease patients with tachycardia, premature beats, or atrial fibrillation, the caffeine and theophylline in tea are stimulants that can enhance heart function. Drinking large amounts of strong tea can accelerate the heart rate, potentially triggering or worsening the condition. Therefore, such individuals should only drink weak tea. Conversely, patients with a heart rate generally below 60 beats per minute should drink more tea, as it is not harmful and can help increase heart rate, complementing drug treatment.

Hypertension patients should not drink strong tea.

"Strong tea" refers to tea brewed with less than 50 ml of boiling water per gram for the first infusion. If hypertension patients drink too much strong tea, the stimulating effect of caffeine can raise blood pressure, which is detrimental to health.

Pregnant women should avoid drinking tea, especially strong tea.

Tea contains large amounts of tea polyphenols, caffeine, etc., which can adversely affect fetal development in the womb. To ensure normal intellectual development of the fetus and avoid excessive stimulation from caffeine, pregnant women should drink little or no tea.

Women during lactation should not drink strong tea.

Drinking strong tea during lactation allows excessive caffeine to enter the breast milk. When the baby suckles, it indirectly becomes stimulated, easily leading to restlessness and frequent crying.

Drink cautiously when intoxicated.

Tea stimulates the central nervous system. Drinking strong tea after intoxication increases the burden on the heart.

Drinking tea also accelerates diuresis, causing toxic aldehydes from alcohol to be excreted by the kidneys before being broken down, which can significantly irritate and harm the kidneys. Therefore, individuals with heart or kidney diseases or poor function should not drink tea, especially large amounts of strong tea. For healthy individuals, a small amount of strong tea may be consumed. After sobering up, methods like eating large amounts of fruit or sipping vinegar can be used to speed up metabolism and alleviate intoxication.

Avoid drinking tea if malnourished.

Tea has a fat-decomposing function. For malnourished individuals, drinking tea to decompose fat can worsen malnutrition.

Avoid drinking tea when having a fever.

The caffeine in tea can not only raise body temperature but also reduce the efficacy of medication.

Be cautious about taking medicine with tea.

There are many types of drugs with different properties, so whether tea can be used to take medicine cannot be generalized.

The tannins and theophylline in tea can chemically react with certain drugs. Therefore, when taking hypnotics, sedatives, iron-containing blood tonics, enzyme preparations, or protein-containing drugs, tea polyphenols easily interact with iron agents to form precipitates. It is not advisable to take these medicines with tea to avoid affecting drug efficacy.

Some Chinese herbal medicines, such as ephedra, uncaria, and coptis, should also not be taken with tea. Generally, it is recommended not to drink tea within two hours of taking medicine.

However, when taking certain vitamin medications, tea has no effect on efficacy because tea polyphenols can promote the accumulation and absorption of vitamin C in the body. Meanwhile, tea itself contains various vitamins and has effects like stimulation, diuresis, lowering blood lipids, and lowering blood sugar, which can enhance drug efficacy and benefit health recovery. Additionally, folk wisdom suggests that one should not drink tea when taking tonics like ginseng and deer antler, which also has some merit.

Avoid drinking large amounts of tea immediately before or after meals.

It is not advisable to drink tea about 20 minutes before or after meals. Drinking tea at this time dilutes gastric juice, affecting food digestion. Moreover, because tea contains oxalic acid, it can react with iron and protein in food, affecting the body's absorption of iron and protein.

Avoid drinking tea before bedtime.

It is best not to drink tea within two hours before sleep. Drinking tea can cause mental excitement, affect sleep, or even cause insomnia, especially with freshly picked green tea, which can easily overstimulate nerves and lead to insomnia.

Avoid drinking overnight tea.

It is best to drink tea freshly brewed. Tea left for too long not only loses nutrients like vitamins but also easily spoils and becomes contaminated. Drinking it can cause illness.

Avoid drinking the first brew of tea.

Because modern tea cultivation, processing, and packaging may involve contamination from pesticides, fertilizers, dust, etc. The first brew is essentially water for rinsing the tea. It should be poured out quickly before adding boiling water again; the tea brewed this way is the most hygienic.

Avoid drinking poor-quality or spoiled tea.

Tea is not easy to store properly and can easily absorb moisture and become moldy. Some people, out of frugality or love for tea, are reluctant to discard moldy tea. Spoiled tea contains large amounts of harmful substances and bacteria and must not be consumed. Even high-quality tea, if brewed and left for too long, can spoil due to oxidation and microbial growth; such tea should also not be consumed.

Children should not drink strong tea.

When tea concentration is high, the content of tea polyphenols is too high, easily reacting with iron in food, hindering iron absorption, and potentially causing iron-deficiency anemia in children. Children can drink a moderate amount of weak tea (about one-third the concentration of adult tea). Preschool children can drink some coarse tea, as it has lower tea polyphenol content.

The elderly should not drink raw tea.

"Raw tea" refers to roasted green tea that is dried directly after de-enzyming without rolling. This tea has a natural green appearance, and its internal components are basically the same as the compounds in fresh leaves. Low-boiling-point aldehyde and alcohol compounds are not much transformed or volatilized, giving it a strong raw, grassy taste. Elderly people drinking this kind of green tea can strongly irritate the gastric mucosa, causing stomach pain after consumption; young people may also feel stomach discomfort, commonly known as "scratching the stomach." If you mistakenly purchase this raw tea, it is best not to brew it directly. You can slowly stir-fry it over low heat in a grease-free iron pan to remove the raw, grassy taste until a light chestnut aroma appears, then it can be consumed.