Biotanika

Serve meat and diairy unfortunately.
Expect this bad point you have a loooot of choice.
Many juices, many vegetal milk, teas, cacao, vegan chocolate, vegan cake, vegan based to bake, fresh fruit an veggies... Also some vegan cosmetics!
And of course everything is organix etc so really nice place to find anything you need. Plus they answer to email if you have any questions.
They also offet teas, coffee and some juice to take there.

You might not want to do all your grocery shopping here but it's great for finding items you might not get anywhere else in town.

Tonnes of vegan milk options, soy products and fresh produce among other things.

One of the first vegan-friendly shop in Łódź, though very expensive. Almost all of the things you can buy there, are cheaper in the internet, even when you include the shipping. Plus many of the things in stock are now available in other "green" shops in Łódź in better prices.
The service is not the most polite one.
The opening hours are weird - almost every time I tried to shop there, it was closed and I'm not a night shopper...

Prices are really reasonable compare with Warsaw. You can find this seitan for 11 zl or soy milk for 6 zl, and also good household stuff. Brilliant in Łodz.

Very nice shop with good stuff. Some of products are expensive but mostly it's not the worst.