Previous studies have shown that tea reduces the risk of heart attacks, improves blood vessel function and recently, researchers have discovered that tea can also prevent ovarian cancer.

Aside from benefic effect mentioned above, green tea might also constitute a starting point in treating a form of adulthood leukemia, known as chronic lymphocytic leukemia, or CLL.

Leukemia is characterized by an excessive production of abnormal white blood cells, overcrowding the bone marrow and often spilling out into the peripheral blood.

The infiltration of the bone marrow results in decreased production and function of normal blood cells. Leukemia, dependent on the type, can spread to the lymph nodes, spleen, liver, central nervous system and other organs or tissues, causing the affected area to swell.

Doctors at the Mayo Clinic, Rochester, Minnesota, have discovered that three in four patients who started drinking green tea or extracts showed a significant improvement of the condition.

Patients had started to drink tea after hearing about a laboratory experiment in which it was observed that a certain compound in tea, known as EGCG, killed cancer cells taken from patients with CLL.

But "these cases alone cannot prove that green tea or its extracts conferred the benefits", Dr. Tait Shanafelt of the Mayo Clinic, who is conducting clinical tests to prove the green tea's benefits, said.