Drinking large amounts of tea could increase the risk of prostate cancer, according to new research.
Scientists found that more than seven cups a day raised the chances of men developing the disease by 50 per cent.
But whether the link is causal or due to coincidence is still unknown.
Study leader Dr Kashif Shafique, from the Institute of Health and Wellbeing at the University of Glasgow said most previous research had shown either no relationship with prostate cancer for black tea or some preventive effect of green tea.
"We don't know whether tea itself is a risk factor or if tea drinkers are generally healthier and live to an older age when prostate cancer is more common anyway," Dr Shafique said.
The Scottish researchers tracked the health of more than 6000 men aged between 21 and 75, over a period of 37 years.
Participants provided information about their tea, coffee and alcohol consumption, smoking habits and general health.
Just under a quarter of the men were heavy tea drinkers. Of these, 6.4 per cent developed prostate cancer during the course of the study.
Those drinking more than seven cups of tea a day were 50 per cent more at risk than those who drank no tea or up to three cups.
The findings are reported in the journal Nutrition and Cancer.