By Wong Mei Ling

Legend has it that more than 4,000 years ago in 2,737BC, tea was discovered by Chinese Emperor Shennong quite by chance. A dead leaf had fallen into his drinking water while it was boiling under the tree.

He unwittingly drank it and was so taken by the refreshing effect of the tea leaf that he named it "cha" (tea in Mandarin).

Tea drinking soon spread across the country and became a symbol of Chinese high culture, which later travelled to other parts of Asia, Europe, the Americas and Russia. However, beyond its social symbolism, tea was an important form of medicine used by early physicians.

Since ancient times, the Chinese have been using tea to improve their health and to cure illnesses, said Mr Chin Chew Seng, a traditional Chinese medicine (TCM) physician and senior trainer at Eu Yan Sang in Singapore.

It is not known when tea was first used for its medicinal value but the earliest records were traced back to the Han dynasty (206BC-220AD).

Today, there are about 1,500 varieties of tea according to the United Kingdom Tea Council. Only the leaves from the camellia sinensis species of plants are considered tea.

Chinese tea is also distinct from TCM tea which is prepared differently and is mixed with herbs and are often drunk for medicinal purposes rather than leisure.

There are six main grades of Chinese tea - white, green, yellow, oolong, red and black.

Indian and Ceylon tea like Darjeeling, Orange Pekoe and Earl Grey are all blends of black tea which are drunk frequently. It's the most popular type in the world.

Based on the level of fermentation, each has different health benefits.

Fermentation is the process of crushing fresh tea leaves and leaving them to ferment. This produces chemical reactions that result in different flavours and colours. The different health benefits of tea have also been attributed to the varying levels of fermentation of the leaves.