Try spreading cinnamon and/or cayenne pepper along the foundation of the house, this worked for me. Also, I've heard talcum powder works and cotton balls dipped in mint oil left near entry points and outside.

I had a problem in the spring with ants and I also wanted an eco-friendly solution. I came across these two options which worked wonders:

Diotomaceous earth: http://en.wikipedia.org/wiki/Diatomaceous_earth
Purchased under the brand name "Concern".

and Borax:
http://www.ehow.com/how_4471409_fight-ants-borax.html

I soaked cotton balls in borax, water and sugar and the ants came to eat and returned the poisoned mixture to the queen.

It's important to kill the queen - then there is nothing left for them to do and they move on or die off.

I hope this works for you!

The Hot Shot liquid ant baits worked for me. The ants consume the poison liquid and take it back to the anthill. You have to place them in areas of high ant traffic for them to work.

Also, find out where the ants are entering your home and seal it completely. This is probably the most important step.

Try pure Boric Acid in powder form where ever you think they are coming inside from. I have used it to great success even better than raid, etc. Had them coming in my kitchen from under a porch perched a few inches from a concrete patio. Put some in the space and even some on the countertop away from where the food is prepared. It is even effective a little wet. It is the active ingredient in Borax but much stronger. You may have to go online or to a pharmacy. Good luck!

I second siobhang's comment about the borax. We had TERRIBLE ant problems (but the little kind, not big carpenter ants), and we used these store bought borax/sugar traps called Terro (www.terro.com) because we were too lazy to make our own. The ants went NUTS and they were gone within a few days. They have several kinds (we used the ones that come pre-contained) and it's safe around pets (we left several traps on the floor and have two cats).

I also sprinkled cayenne and sprayed vinegar along baseboards, and that worked for a few days, but when we tried the Terro stuff that seemed to solve the problem. We got the Terro traps at Target/Home Depot/Ace Hardware. Raid traps don't do jack, don't bother with those! Good luck!

How timely, I'm doing a Re-Nest post on diatomaceous earth tomorrow.

As siobhang said, it IS most important to kill the queen. I have had great luck with the boric acid/sugar water solution. The trick is to get it at the right ratio (and some ants like fat more than sugar, so peanut butter can be a useful addition). I use bottle caps or put a large drop on wax paper and lay it in the way of the ant trail. I do my best to follow the ant trail outside and lay the bait there...leaving them little reason to come indoors. Then I caulk and use expansion foam to seal up as many cracks and crevices as possible.

Be patient with the boric acid...it can take as long as a week to see the trail fall off, but when it does you'll know you've gotten to their nest!

I myself have a serious ant problem. I got the exterminator in and he sprayed the anthills outside and said they would be gone in a day or two. That did not work as I saw the ants crawling about after I dug them up with the spade. Money down the drain there. He did say to get rid of all the wood stumps that are lining the gardens etc. as that is what they seem to like. I understand from my ant that cucumbers do the trick. I will give that a try as well as the borax. I saw the boxes at the supermarket here. Thanks for the tips that work.

Terro Borax, Terro Borax, Terro Borax! It's a $3 box and it WILL work. I had a serious ant problem much like yours, and I bought the liquid borax Terro kind. You squirt out small globs onto the little square cardboard pieces in the kit, and place them along the trail(s) of the ants (if you have more than one trail going around, buy 2 or 3 boxes and use everything). It might take a few hours before they start going after it but they will, and then they will keep eating it as long as you refill the liquid globs every day. I noticed only a couple ants remained after one week, and then none after 1 1/2 weeks. That was 3 months ago, and all summer long they have not returned. Not one. I feel like I should charge my landlord for my terminator services. Good luck!

There is a big difference between little sugar ants and big carpenter ants. I used to always get little sugar ants in my house, and any ant bait seemed to clear up the problem in a couple of days.

But carpenter ants are pretty resistant to "regular" bait. I worked at a non-profit that was in a gorgeous old wood Victorian home, and we had a terrible problem with carpenter ants. I tried all the "regular" commercial products, and finally called an exterminator. He said carpenter ants eat different things - mostly wood (hence, Carpenter ants), and so are not attracted to the normal bait. Now, I can't remember WHAT he used (if he even told me), but I know that we, too, were told to keep wood chips out of any plant beds near the house. Whatever he did eliminated the problem.

I don't know if Borax would have worked - I never tried it. I know it would work for sugar ants, I don't know about carpenter ants.

Johnson's Baby Powder works for me. I first used it just to locate the cracks where the ants were getting into my kitchen, and low and behold, it killed them. Plus, they drag it back to their nest infecting even more ants. Once I saw where they were getting in, I just kept that area covered in powder, and no more ants.

Before I discovered baby powder, I used Bengal. It is a pesticide company in Louisiana, and Louisiana has huge ants and roaches. I spray Bengal around to discourage roaches, but it also wipes out ants. Bengal is pretty rare, and I don't think insects have developed a resistance to it yet. Bengal is sold directly on their web site, or on Ebay, as Bengal Roach Spray. I suggest the Gold. It's the strongest, and the best, IMHO.

TERRO ANT BAIT

I've tried all sorts of products, but this is the only thing that worked.

I had ants infest my car. My CAR. I was driving and trying to avoid ants at the same time. It was nuts. Just put out the baits (the prefilled ones aren't worth it...buy the kind that just comes in a bottle), and watch the ants flock to the stuff. They think they've hit the jackpot, and you'll see an alarming number of ants come and get the stuff. They take it back to the nest and literally overnight, the amount will reduce by a TON. You'll be surprised by how few there are. Leave it for another night, and they'll pretty much be gone.

For a natural solution, I've heard that both baking soda and rhubarb work to get rid of them. Not sure if there is any truth to that, but worth looking into.

SPLENDA! If you put out splenda they will eat it and die. Splenda was originally made as a bug poison. Google it online and you'll find it has worked for many people.

Another vote for boric acid! I read that it might take a few days, but in our case it only took 3 hours. I used little lids, made a thickish liquid solution of borax, powdered sugar and water, and that did it.

That did it for the regular variety of ants, but then we got an infestation of Pharoah Ants -- tiny tiny brown ants. Since they are meat-eaters (they came for the dry cat food kibble), the sugar solution didn't work. I scrubbed with borax, left lots of borax out, and removed the cat food.

So your solution depends on what sort of ants they are, and what sort of appetites they have... You may need to try several different things...

p.s. Here in Switzerland, the only place we could find borax was to ask the pharmacist -- there is nothing on store shelves anywhere. It was actually very funny, because after my husband asked for some, the pharmacist dropped his voice discreetly, and asked for confirmation that it was for foot odor, while trying to get a look at the size of my husband's feet! My husband told the pharmacist what it was for, and he was incredulous -- had never heard of using it on ant! (we use borax for lots of things, and so it is funny that they just don't here).

All this to say, if you can't find it on store shelves in Saudi, you might be able to get it from the pharmacist...

Put a cap filled with honey outside your door (or where the ants are coming in). The ants stop at the honey and go no further.

In college my roommate and I purchased a large potted plant for our dorm room, only to find it came with an ant nest. So we got sugar packets from the cafeteria and sprinkled into the soil and the ants almost never left the pot. If we spot an occasional ant on the floor then we know it's time to "feed the ants" and get more sugar packets and the ants go back to the potted plant.

If you don't feel like (or agree with) killing the ants, you can use a diluted orange oil to clean with. Ants will not go into an area with orange oil. It also makes the area smell nice!

"I understand from my ant that cucumbers do the trick..."
I wouldn't consult a pest for advise on pest removal.

I live in a basement and have this problem. We ended up having success by putting an ant feeder on the opposite side of the yard (a covered bowl with sugar). Then, we sprayed all entry points with a vinegar/orange oil solution with a few drops of dish soap. Our cats took care of whoever was left in the house, and they never tried to come back in. Why go through something yucky when a delicious meal is right there waiting for you? You will have to check the species of ants in your neighborhood and make sure you fill your feeders with food they will eat.