From one of the manufacturer's that uses Borax for that purpose...

TERRO® Liquid Ant Bait is a sweet food based product similar to pancake syrup combined with Borax. Borax is a mineral that is mined in the desert in California and is a common active ingredient that is used in soap
products such as 20 Mule Team Borax.

The product kills ants but will not harm people or pets. If you spill some
on your skin there will be no reaction at all. Simply wash with warm water.