Greenpeace has really done it this time. It’s taken the ethical consumer iPhone app concept, popularized by GoodGuide and its ilk, and flushed it down the toilet.

I’m being cheeky (ha!), but the app is real. It’s called the Tissue Guide, and it serves a very specific purpose: to help shoppers choose environmentally friendly brands of toilet paper, napkins, paper towels and facial tissues.

Naturally, as soon as I heard about this app, I had to download it. How could I not? One commenter who gave Tissue Guide a five-star rating described it as “solid.” I mean, honestly.

But in the non-4-year-old sense of the word, the app is pretty solid. It’s free, and it contains info on more than a hundred brands of paper products, which are sorted into three categories — “recommended,” “could do better” and “should be avoided.” I was happy to see that the Trader Joe’s toilet paper I buy was on the recommended list, made of 100% recycled paper, 80% of which is post-consumer. (I chose not to think about that last part too hard.) The app also takes each product’s bleaching process into consideration as well.

According to Greenpeace, Americans could save more than 400,000 trees if each family replaced one roll of virgin toilet paper with one roll of recycled toilet paper. So, even though the thought of using a $200 phone to shop for TP is a little goofy, I actually think Tissue Guide is a useful tool. I love it when technology allows me to be a smarter consumer. Because that’s how I, um, roll.