Crack open a cooked lobster and you may find a bright green, paste-like substance tucked inside the body cavity. Known as tomalley, this substance has long divided seafood lovers — but medical professionals and environmental scientists are increasingly clear: for most people, it is best left on the plate.
En bref
- —The green substance in lobster is the tomalley, its liver and pancreas
- —It concentrates heavy metals and pollutants from ocean water
- —Doctors warn older adults and pregnant women especially to avoid it
Tomalley: the lobster’s built-in filtration organ
When a cooked lobster is cracked open, the bright green paste visible in the body cavity is called tomalley. Despite its striking appearance, it is not a seasoning or a byproduct of cooking — it is a functional organ.


