From the entry on p45 for the SSRI anti-depressant citalopram (trade name 'Cipramil') in The Psychotropic Drug Directory 2001/02 by Stephen Bazire (ISBN 1856421988): "The green and yellow 20mg pack in the UK has led to increased use among football supporters in the author's home city of Norwich."
You read that correctly - soccer fans in Norwich City are taking medication based on the fact that the colors on the box match the colors of the local soccer team. I can't imagine why they're depressed... Get a life people! And this is coming from someone named YodaYid.
p.s. I wonder what would happen if they packaged estrogen supplements in those colors. How far does team loyalty go over there?