If you want the most effective cockroach killer, bar none, than Bayer Maxforce FC Magnum Cockroach German Roach Pest Control Gel Bait is the one for you. It works in two ways. When a cockroach feeds on it, just one feeding will kill the roach. However, if a cockroach merely comes into contact with this gel, it will absorb enough of the toxins, through its body, to cause its demise. If the roach feeds on it, it will leave feces that are also toxic to any other roach that comes into contact with them. The active ingredient is fipronil, a nervous system disrupter. The fipronil gel is injected under cabinets, cupboards, along roach runs in dark places and anywhere there might be a roach gathering. It won't dry out for up to 1 year, and it will give continuous protection during that time.
Boric acid has been one of the most often used and effective ways to rid your dwelling of cockroaches, and Harris Boric Acid Roach Powder with Lure has a food attractant added to their boric acid to make it even more effective. It works in two ways. The boric acid is poisonous if ingested, but it also will be absorbed through the skin if walked on. It comes as a powder and is "puffed" or blown into known cockroach habitat areas. The food attractant, usually grains of sugar or flour, ensure that the roach will eat some. Boric acid is time tested and effective, but it is toxic to kids and pets. Always make sure it is applied in areas that are not readily accessible to either, and this boric acid formula also comes in tablet form to best suit your needs.
For one of the safest roach killing methods on this list, try Combat 41913 Source Kill Roach Killing System. It uses hydramethylon as its active ingredient, which is distributed in covered bait stations. Although not tamper proof, it still makes them more difficult to accidentally ingest and therefore, they can be placed more out in the open. Lay them behind toilets, on top of counters and places where roaches like to congregate. Hydramethylon essentially breaks down a roaches metabolism, It is a slow kill ingredient that allows the roaches to take particles back to the nest where others might feed on it and also die as a result.
From one of the most respected insecticide companies around, Raid Max Roach Killer kills roaches both on contact and for up to 6 months afterwards. It is made of synthetic pyrethrins, which are natural insecticide ingredients that come from the chrysanthemum plant. If spot sprayed on a living roach, it will die virtually instantaneously. However, the formula is infused with petrochemical oils which means the pyrethrin ingredients won't soon evaporate, and they keep on being effective for up to 6 months. This is not a bait, so a roach must physically come in contact with this substance for it to be effective. Spray heavily where there is known roach traffic, and when they come into contact with Raid Max, that's all she wrote!
One of the most unique ways to eliminate roaches is Black Flag Roach Killing Chalk. You simply draw a line of chalk over known roach trackways, like where molding connects to a wall or floor, and when a roach walks onto the chalk, it will receive a lethal dose of the synthetic pyrethrin active ingredient. You can use this chalk to draw a barrier around foodstuffs or water supplies, forcing roaches to walk over it when they want to eat or drink. Once they cross the line, they'll never cross it again. It lasts for up to 8 weeks, is easy to apply and can be used under cabinets, around pipes, on baseboards and virtually anyplace where roaches travel.