Researchers have recently figured out that if you lace a highly attractive food with a small amount of slow-acting insecticide the results are better. Roaches find the bait, eat it and thereby contaminate themselves with the insecticide. Now they have time to get back to the harborage (a safe area inside a wall where cockroaches congregate, a simple type of "nest") where they contaminate their mates and disrupt the whole colony. Baits take longer to work but they offer the promise of complete control of even large infestations.
Professional versus consumer-level baits
There are many cockroach baits on the market, some are even sold through grocery stores and the like. Because the new baits are significantly more expensive then the older products they have been relegated to "professional" status. This is unfortunate because it makes them harder for the consumer to find and the result is many people faced with a cockroach infestation resort to insecticide sprays, the old, failed spray and pray method. The good news is that professional-quality baits are now available as well but you have to shop online to find them.
I have posted a revised page about these new baits at our 'Bugs site (click here) including a link to an online source.