Korean company WONYONG markets a product called Π-Water.  The site is in English, though some of the translations are a bit rough.  From what I can tell, “Π-Water” (which also may be known as “Tarama Water”)  seems to be some sort of  drinking water, designed to mimic the water found inside the cells of living organisms.   They suggest that it can also be used in food preparation, agriculture, and even in swimming pools.

I’m not entirely sure what this product has to do with Pi, thought the bottles are round.  I’ve never seen this product on the shelf in the US or southern Europe (or anywhere else, for that matter), nor have I seen it sold online anywhere.

There are probably many products that use the letter π in their name, like π perfume.