- German
- 10–15 mm, light brown, two dark stripes behind the head
- Oriental
- 20–25 mm, dark brown to black, shiny
- Active
- At night
- Peak season
- All year, worse in summer
Small early problems can respond to gel baits, but German cockroaches multiply so quickly, and spread so easily between flats, that professional treatment is usually the reliable route.
Signs of cockroaches
- Cockroaches scattering when you switch on the kitchen light at night
- Droppings like ground black pepper or coffee grounds in cupboards and drawers
- Small brown egg cases in hidden corners
- A musty, oily smell in heavy infestations
- Shed skins behind appliances
How to be sure
German cockroaches are light brown with two dark stripes and live high up in warm kitchens: behind fridges, cookers and dishwashers. Oriental cockroaches are larger, dark and shiny, and favour drains, damp basements and ground floors.
Small brown beetles in cupboards are more often biscuit beetles. See our pantry pests guide.
What you can do yourself
- Place cockroach gel bait in small dots in cracks near where you've seen them: behind and under appliances, inside hinges, around pipes.
- Don't spray insecticide near the gel. It repels cockroaches from the bait.
- Clean grease from behind cookers and fridges and don't leave food or dirty dishes out overnight.
- Fix dripping taps and leaks, since they need water.
- Seal gaps around pipes and under kitchen units.
Call a professional if
- You see cockroaches in daylight, which suggests a large population
- You live in a flat or shared building. They travel through service ducts between homes
- Gel baits haven't reduced numbers within two to three weeks
- You run any kind of food business from home
Safety: Cockroaches can spread bacteria onto food surfaces and their droppings can trigger asthma and allergies. Clean surfaces before preparing food.
Keeping them out
- Check deliveries, second-hand appliances and boxes from storage
- Keep kitchens free of grease build-up behind appliances
- Seal gaps where pipes enter walls
Kit that helps
- Cockroach gel bait
- Monitoring traps for insects
- Sealant for pipe gaps
Product types only. We'll only ever point you to things we'd use ourselves.
Questions people ask
Do cockroaches mean my home is dirty?
Not necessarily. They arrive in deliveries and travel between flats through shared ducts. Cleanliness affects how fast they spread, not whether they turn up.
Can cockroaches survive a nuclear blast?
No, and they don't survive good treatment either. Gel baits are effective because cockroaches share them back in their hiding spots.
Will a council treat cockroaches?
Some councils do, usually for a fee. In blocks of flats, the landlord or managing agent may need to arrange treatment for the whole building.