This leaf is both bitter and astringent but extremely good for health.

According to Traditional Medicine Practitioner Bui Dac Sang, Hanoi Oriental Medicine Association, guava leaves are known as "miracle drugs" because they contain many beneficial compounds. Young guava leaves or young buds of guava leaves contain about 3% resin and 7-10% tannin, antioxidants such as vitamin C and flavonoids, antibacterial and anti-inflammatory substances.

Guava leaves reduce blood sugar levels, preventing the body from absorbing sucrose and maltose. Studies have also shown that guava leaves can improve symptoms of diabetes such as increased insulin and insulin resistance. You can use guava leaves by making tea and drinking it daily for 12 weeks to see clear results.

Guava leaves are also used in the treatment of allergies. Compounds in guava leaves prevent the release of histamine - the main cause of allergies. Guava leaves stimulate the production of digestive enzymes, help destroy bacteria in the intestinal mucosa, and prevent the growth of toxic enzymes caused by bacteria.

In Oriental medicine, guava leaves are a herbal remedy for diarrhea. To treat diarrhea, boil 30 grams of guava leaves with a handful of rice flour in 1-2 cups of water and drink twice a day. In case of dysentery, cut the roots and leaves of the guava tree, boil for about 20 minutes, filter the water and drink daily until the disease subsides. To relieve stomach pain, boil 8 guava leaves in 1.5 liters of water and drink three times a day.

Guava leaves are effective in removing pimples and dark spots on the skin. Guava leaves contain antiseptic properties that kill acne-causing bacteria. Use by washing the guava leaves, pounding or grinding them and applying them to the pimples after cleaning. For blackheads, pound guava leaves and mix them with warm water, wash daily, and gently rub them on the acne areas to help remove them quickly.

Due to its anti-inflammatory properties, guava leaves are often used as an ingredient in toothpaste, to cool the mouth, relieve toothaches, treat gum disease, mouth ulcers and treat sore throats. Guava leaf tea can be used as a mouthwash or a natural paste can be made at home to brush your teeth.

Scientists at Krupanidhi Medical College, India, discovered that guava leaf powder can protect the liver from damage. Tests on mice showed that mice fed guava leaf powder were protected from chemical-induced liver damage, while mice that were not given the powder suffered severe liver damage. Experts believe that the antioxidants in guava leaves are responsible for the disease prevention.

People use guava leaves to make tea products, exported to European and North American countries. To prepare a cup of guava leaf tea, soak a handful of guava leaves in hot water for about 15 minutes, filter the water, remove the leaves. Boil this water with tea to drink, or brew it with hot water with green tea leaves to drink during the day, which is good for your health.