Red ants, or harvester ants, rarely trouble humans. If you have a nest in your yard that is destroying your garden or invading your home, you can use borax to get rid of them.
Borax, a naturally occurring boron compound, kills insects including red ants when they eat it. Ingested borax destroys an insect's digestive system. Red ants eat borax directly if it is mixed with bait like sugar or flour. If an ant walks through borax, it will later ingest the powder when it grooms itself.
To kill red ants inside your home, mix 1 tsp. of borax into 1/2 cup honey. Leave the mixture where you have seen the ants. They will be attracted by the honey and killed by the borax. If you need to kill red ants outside, sprinkle a mixture of one part borax and one part sugar around the outside of the nest. The ants will either eat the borax or walk through it, taking it down into the nest.
Borax will not kill humans or animals, but it can make them sick if they eat it. Keep any honey traps away from places where pets or children might find them. If you sprinkle borax outside, fence off the area to be sure no unsuspecting child or animal wanders into the mixture.