Black ants are a nuisance around the house. They get into pet food, ruin food in the cabinets and eat crumbs off the counters. The best way to kill black ants is with a combination of natural and chemical items.
Environment, Health and Safety Online touts the virtues of "instant grits." Pour the instant grits around ant-infested areas and around any entry point into your home. The ant eats the grits, which later expand when the ant drinks water, killing it instantly.
Use bait stations or gel bait, recommends the University of California. The baits and gel contains chemicals that the ants ingest and carry back to the nest. The ants infect others in the nest, killing the entire colony.
Avoid using gel bait if you have small children or pets in the house. The gel isn't covered the way bait stations are and may cause health problems if pets or children eat it.