American cockroaches eat almost anything organic, with a strong preference for decaying matter. Their diet spans an impressive range: cheese, beer, leather, bakery products, bookbinding glue, hair, flakes of dried skin, dead animals, plant materials, soiled clothing, and even the starch sizing on glossy paper. This flexibility is a big part of why they’re so hard to get rid of once they move in.
Preferred Foods and Materials
While American cockroaches will eat nearly anything, they gravitate toward food that’s already breaking down. Fermenting fruit, rotting wood, leftover grease, and food scraps in garbage bins are prime targets. Starchy and sugary foods rank high on their list. In lab settings, young cockroaches showed the strongest attraction to dextrin and corn starch, both simple carbohydrate sources. Bread, cereal, potatoes, and anything baked will draw them in quickly.
What surprises most people is the range of non-food items they consume. American cockroaches readily eat leather goods, wallpaper paste, book bindings, manuscripts, and cardboard. They’ll feed on human hair, fingernail clippings, and dead skin flakes that accumulate in bathrooms and bedrooms. Pet food left out overnight, crumbs behind appliances, and even beer residue in recycling bins all serve as meals. In outdoor environments (where they actually prefer to live in warmer climates), they feed on leaf litter, tree bark, fungi, and smaller dead insects.
How They Digest Such a Wide Range of Materials
The secret to their extreme dietary flexibility lives in their gut. American cockroaches harbor a dense community of microorganisms in their hindgut that break down complex materials their own digestive enzymes can’t handle. Bacteria from several major groups act as primary fermenters, dismantling plant-based fibers, starches, and even wood-derived compounds into simpler molecules the cockroach can absorb.
These gut bacteria produce hundreds of specialized enzymes that target different types of carbohydrates. Researchers cataloging the genetic toolkit of these microbes found 248 unique families of carbohydrate-breaking enzymes across the bacterial community. Some of these enzymes specifically target xylan, a structural component of wood and cereal grains. Others form multi-enzyme complexes (similar to those found in termite guts) that cooperate to dismantle tough plant fibers. This internal chemistry lab is why a cockroach can eat a piece of cardboard or book binding and actually extract nutrition from it.
How They Find Food in the Dark
American cockroaches are nocturnal foragers. They spend daylight hours hiding in warm, dark, moist spaces and emerge after dark to search for food. Their antennae are packed with chemical receptors that detect food odors at remarkably low concentrations, allowing them to home in on crumbs, grease residue, or pet food from across a room. They also follow scent trails left by other cockroaches, which is why infestations tend to concentrate around reliable food sources like kitchen cabinets, garbage areas, and drains.
They’re not picky, but they do have priorities. Given a choice, they’ll pick moist, starchy, or fermenting foods over dry ones. This is partly practical: cockroaches need water even more urgently than food. They can survive about a month without eating, but only about one week without water. That’s why you’ll most often find them in kitchens, bathrooms, basements, and around leaking pipes, where moisture and food scraps overlap.
What Young Cockroaches Eat
Nymphs (the immature stages) eat the same general categories of food as adults, but they show a stronger preference for simple starches and carbohydrates. Lab studies found that dextrin and corn starch, alone or mixed together, were the most attractive food sources for American cockroach nymphs. This makes sense biologically: young cockroaches are growing rapidly and need easily digestible energy sources. They also practice coprophagy, consuming fecal pellets left by adults. This serves a dual purpose, providing nutrients and seeding their developing gut with the bacterial communities they’ll need to digest tougher materials as they mature.
Why Their Diet Matters for Pest Control
The fact that American cockroaches eat almost anything is both the problem and the solution when it comes to managing them. On one hand, eliminating every possible food source in a home is nearly impossible when the pest can survive on envelope glue and skin flakes. On the other hand, their willingness to eat almost anything makes them highly susceptible to baits.
Commercial cockroach baits exploit this indiscriminate appetite by combining multiple food attractants, sometimes as many as 11 different ingredients in a single product, with a slow-acting insecticide. The cockroach eats the bait, returns to its hiding spot, and dies. Other cockroaches then feed on the dead one (or its droppings), spreading the poison through the colony. Rotating between bait formulations with different attractant bases helps prevent the rare cases where a population starts avoiding a particular product.
Reducing available food and moisture remains the most effective long-term strategy. Store dry goods in sealed containers, clean grease from behind stoves and refrigerators, take out garbage regularly, fix leaky pipes, and don’t leave pet food out overnight. You won’t eliminate every possible food source for an insect that eats dead skin and book glue, but cutting off the easy, high-calorie options forces them to work harder and makes baits far more effective by reducing the competition.