**1. Introduction**

Scented tea, also known as fragrant tea, is made from the flowers or leaves of plants. It is a type of reprocessed tea unique to China. It uses the properties of tea that make it good at absorbing odours and blends scented flowers and tea together. The tea absorbs the fragrance and then the dried flowers are removed using a sieve. The resulting scented tea has a strong fragrance and a bright tea drink. Scented tea has a long history of production. As early as the Song Dynasty, spices were added to green tea as a tribute to the emperor [1]. The processing technology of tea gradually matured during the Ming Dynasty and the scenting method of scented tea has since progressed [2]. The quality of scented tea is related to the scenting process. Mature scenting processes, such as moisturising continuous scenting, frying flower processes and innovative drying methods can be used to ensure that the scented tea maintains appropriate water content during the scenting process and improves the ability of the tea base to absorb the fragrance of the flowers. Chinese scented tea is mainly

produced in the Guangxi, Fujian, Yunnan, Sichuan and Chongqing provinces. In 2021, the scented tea output in China was 2.917 million tonnes. Scented tea has been exported to Japan, the USA, Russia, Germany and other countries for many years and has a good reputation in local markets.

Scented tea contains various nutrients, such as proteins, amino acids, tea polyphenols, tea polysaccharides, vitamins and minerals. It also contains pigments, taste substances amino acids, catechins, caffeine and aroma substances. These substances not only improve the quality of scented tea but are also required for human physiological activities and contribute to the health effects of scented tea. Protein and amino acids are essential components of human metabolism. The water-soluble protein content of scented tea is around 2% and can be directly absorbed and used by the body through drinking the tea [3]. Scented tea is rich in amino acids, including theanine, glutamic acid and aspartic acid as well as vitamins. For example, jasmine scented tea contains 80–90 mg of vitamin C per 100 g of jasmine scented tea and can improve the immune system [4]. Scented tea also contains mineral elements, such as phosphorus, potassium, calcium, sodium, magnesium and sulphur as well as trace elements, such as iron, manganese, zinc, selenium, fluorine and iodine. In addition, the polyphenolic compounds, tea polysaccharides, caffeine and other components present in scented tea have good health effects on human physiological activities [5]. Scented tea also contains aromatic substances, including esters, alcohols and hydrocarbons, among which linalool, indole, benzyl alcohol and methyl salicylate are the main aroma components. These aromatic substances can aid digestion, relieve stomach pain and calm and regulate the nervous system [6]. Scented tea has the same refreshing effects as coffee due to its high content of caffeine and alkaloids, which are central nervous system stimulants. However, drinking coffee regularly may cause arteriosclerosis, whereas drinking scented tea can avoid this adverse effect. Scented tea contains polyphenols and vitamin C, which can effectively eliminate the adverse effects of caffeine. On the other hand, the caffeine in scented tea can promote gastric secretion, help digestion, enhance fat metabolism and effectively reduce body mass index [7]. Therefore, scented tea can also be used to promote weight loss. Scented tea contains a large amount of vitamin A, vitamin C and other trace elements that protect the eyes and have therapeutic effects on dry eyes caused by overuse of the eyes. Traditional Chinese medicine also commonly uses scented tea for the treatment of eye diseases [8]. Several cell and animal studies have shown that tea polyphenols, polysaccharides and pigments have significant anti-cancer and anti-tumour effects. The main anticancer pathways include inhibiting cancer cell proliferation, regulation of signalling pathways to induce apoptosis of cancer cells, inhibition of angiogenesis, inhibition of metastasis and infection of cancer cells and inhibition of tumour immune escape mechanism [9–11].

The pharmacologist Li Shizhen's 'Compendium of Materia Medica' also records the health care effects of scented tea. The chemical composition and health functions of scented tea have been extensively studied over the past two decades to examine the mechanisms behind the health benefits of scented tea. The scientific community and mass media have gradually begun to pay attention to the beneficial properties of scented tea. For example, drinking scented tea is associated with anti-oxidant [12], anti-cancer [13], hypoglycaemic [14], hypolipidaemic [15], immunomodulatory [16] and neuromodulatory [17] effects. This chapter mainly reviews and discusses the health functions related to scented tea and the direction of future research and development.

*Research Progress on the Health Benefits of Scented Tea DOI: http://dx.doi.org/10.5772/intechopen.106605*
