The first time you see it, your stomach drops. That strange green goo hiding inside your perfectly cooked lobster leaves you wondering if it is poison, a delicacy, or something you should never swallow. Known as the “tomalley,” this vivid green smear is actually the lobster’s liver and pancreas.

Because this organ filters and digests everything the animal consumes, it can be a highly controversial food choice. Some seafood lovers worship its deep, briny richness, spreading it on warm bread or whisking it into sauces, while others push their plates away in disgust.

While tomalley can be safe in small amounts, it is also where environmental toxins, heavy metals, and dangerous algal pollutants accumulate. Because it acts as a filter for the ocean, scientists warn that it can quietly store the water’s dirtiest secrets.

Ultimately, the choice to eat it is entirely yours. You should inspect your seafood carefully, enjoy the green stuff sparingly if you choose to try it, and never feel pressured to eat anything on your plate that makes you uncomfortable.