First, try to use some citrus juice to repel the ants. Lemon or orange juice freshly squeezed near where the ants traverse is going to make them try to avoid these areas. If this is the entry from the outside, you may be able to remove the problem altogether. If this doesn’t work, you can mix borax, sugar, and water in order to create a tasty, yet poisonous mixture for the queen of the ants. This can be toxic for pets and children so be careful if you have either of these. If none of this works, you can place enough diatomaceous earth so that the ants become dehydrated and die without putting any toxic materials around your home. Original source: How to Get Rid of Ants