It won’t hurt. Green tea is a source of the highly potent antioxidant catechin, which neutralizes free radicals circulating in your body due to the natural oxidation process. In 2006, researchers at the Boston University School of Medicine studied rabbits with erection problems, and gave them a number of different juices and teas to see if they had any effect.
They concluded that long term consumption of foods naturally rich in antioxidants (including green tea) reduced erectile dysfunction by increasing blood flow and smooth muscle relaxation. So if you have some green tea in your cupboard, it’s easy enough to try. But don’t expect changes overnight.
Any changes noted by researchers were noticed after long term consumption of green tea.