Cornmeal and red pepper are both very effective non-toxic household items for fighting ants. A common misunderstanding, however, is that the two products should be mixed together. This isn't the case since they actually work contrary to each other. Cornmeal is an attractive food source for ants, while red pepper works as a repellent. You don't want to call them to you with cornmeal, only to shoo them away from a tasty bait.
Locate the areas where ants are entering your home. Sprinkle liberal amounts of powdered red pepper at these sites. Ants and most other insects are completely repelled by red pepper, which also acts as a natural killer.
Sprinkle red pepper anywhere you see ants trailing each other. They're leaving their scents behind for followers. Red pepper neutralizes the scented areas and put a stop to their trailing.
Dump red pepper on and down into any ant holes or nests that you find outside.
Fill plastic bottle caps with cornmeal. Set the little baits anywhere you've seen ant activity. Places of special interest include anywhere water is consistently present in the home such as kitchens, bathrooms and laundry areas. Ants eat the cornmeal, can't digest it and succumb to gas attacks.
Sprinkle ant nests with cornmeal. Replace as necessary, particularly after rainfall. Cornmeal won't work anymore once it's been wet.
Mix equal parts cornmeal and boric acid if you're in a hurry for the kill. Fill plastic bottle caps with the mixture and set them in locations where ant activity has been noticed. They'll take the bait back to the nest and the entire colony will be killed by either cornmeal or boric acid. Take care with placement of these baits as boric acid may be toxic to children and pets.