Tea (Camellia sinensis) is one of the most widely consumed beverages in the world. Studies have revealed that a higher consumption of green tea has been found to be associated with a lower prevalence of cognitive impairment in humans. At the same time, findings from numerous cell culture and animal studies suggest that green tea extract termed EGCG - (-)-epigallocatechin-3-gallate, may be a source of neuroprotectants, with particular relevance to AD and other neurodegenerative diseases where oxidative stress has been implicated. We now wish to conduct the first large scale human trial to examine whether EGCG has a cognitive enhancing effect in patients with mild to moderate Alzheimer's Dementia. EGCG will be given to Alzheimer's Dementia patients as an adjunct to their current medication. The results of the study may help to better understand how we may treat Alzheimer's disease and may have important consequences for the public health system and to reduce also the burden for carers. The study will be carried out across several universities and hospitals and in collaboration with Alzheimer's Australia.