1. Improve digestion: Oolong tea contains more polyphenols and catechins, which can stimulate intestinal peristalsis, promote digestion, help food digestion and absorption, and relieve stomach discomfort.

2. Reduce blood lipids: Tea polyphenols and catechins in oolong tea can prevent the oxidation of lipids in the human body and reduce the levels of cholesterol and triacylglycerol, thus reducing the risk of cardiovascular diseases.

3. Protect the heart: Oolong tea contains some aromatic compounds, such as caffeine and theanine, which can improve heart rate and metabolism and protect the heart.

4. Eliminate toxins in the body: Oolong tea is rich in antioxidants, which helps to eliminate harmful toxins in the body and improve health.

5. Lose weight: Tea polyphenols and various amino acids in oolong tea can accelerate the activity of lipolytic enzymes, promote fat metabolism and help to lose weight.

The main side effects of oolong tea are:

1. Oolong tea contains caffeine. Drinking too much will cause nervous overexcitation, palpitation and other uncomfortable symptoms, which is not suitable for patients with hypertension and heart disease.

2. Oolong tea also contains a lot of tannic acid, which will combine with iron and hinder the absorption of intestinal iron, and is not suitable for patients with iron deficiency anemia.

3. Oolong tea is very irritating to the gastrointestinal tract, and it is easy to cause indigestion, diarrhea and other reactions. Therefore, fasting or heavy drinking should be avoided.

Oolong tea contains some catechins, which may cause allergic reactions in some people. Stop drinking immediately if you have symptoms such as skin allergy and poor respiratory tract.