Camellia sinensis is a plant growing in India, Sri Lanka, Java, Japan and its properties were known 4000 years ago. Since then, traditional Chinese medicine has recommended this plant for headaches, body aches and pains, digestion, depression, detoxification, as an energiser and, in general, to prolong life. Tea contains volatile oils, vitamins, minerals, purines, polyphenols, particularly carechins. We have analysed ten commercial teas from various countries to determine their mineral composition and we have analysed a green tea, an Oolong tea and a White tea to determine their polyphenols and flavonoids content. Our study shows that the variation of mineral composition, polyphenols and flavonoids are linked to different origins of the plant. For the determination of phenols compounds and flavonoids we used an HPLC apparatus and for mineral analysis an atomic absorption apparatus.