Does Ant Chalk Really Work?


Does ant chalk really work? I decided to find out by holding a couple of basic experiments in our Thai village garden to see if the Chinese made, ‘Miraculous Insecticide Chalk’, would get right up an ant’s nose and send it packing to pastures new.

Ant Chalk – The Big Test – Sweet Piccallili

Ants can be a real pest (pun or no pun. Up2You) at the best of times, roll out a red-hot Thai summer’s day and ants are an absolute nuisance. They are known as social insects but ‘annoying buggers’ would be a far better descriptive term. Ant chalk is used to deter or kill them.

Ant chalk is used in Thai villages (towns and cities too) to thwart the onwards and upwards march of ants. Village shops sell it and use it too – that’s a positive thumbs-up for the product. The chalk is usually seen drawn in a circle around shop table legs which have sweet things and cooked meat for sale on top. The theory is the ants won’t cross the chalk line and that stops them from scaling the table legs to masticate on the food displayed. Read it again…. it says masticate.

ant chalk test

The first test wasn’t a major success because there weren’t enough ants about despite me putting down a teaspoon of Papa Farang’s delicious sweet piccalilli for them to chew on. The piccalilli attracted some interest but not overly so.


I cleared the ants away with a few Subbuteo style flicks and drew a square chalk line around the sweet piccalilli – that’s a difficult word to spell (piccalilli) but a very easy and fluent one to type – and then walked away and returned 15 minutes later. Would the sweet piccalilli be swarming with ants or would it be exactly as I’d left it?


The picture isn’t too clear because I got my big head in the shot but the hand-out from that is anyone doing a Google search with the words – Big Head + Masticate –  should land on this page. So did the test prove ant chalk works?

By the time I returned the sweet piccalilli had dried out in the blazing sun but there were no ants feasting on it and no live ones in the square, only two dead ones. The ant chalk is toxic and banned from most Western nations but still widely available in countries like America via the internet  and Chinatown markets.

There were a few ants patrolling the area to the left of the chalk square but none attempting to cross the line. The experiment seemed to prove ant chalk worked but I needed further proof and decided to dry run the chalk test again with some cheese savoury biscuits. The area around our garden table had a small army of ants ‘socializing’ and searching for food, it was the ideal spot for the test. Our Shih-Tzu dog, Tang Moo, decided to join in as well.

The Ant Chalk Test – Take Two – Cheese Biscuits


Tang Moo was keen to get started and even more so to check if the cheese savoury biscuits were satisfactory or a garden-variety, run of the mill snack.


I placed two cheese biscuits inside a chalked square and one outside by its top right corner. Within seconds ants had swarmed all over the single biscuit and were feasting like crazy on it.


The biscuits inside the square did attract some attention but only about a half-dozen or so ants went inside the chalk box. In the right corner of the photograph you can just make out the single biscuit being partied-on. So what was my conclusion?

I believe ant chalk does work, not 100%, but if drawn around table legs any ants that crossed the line would either be dead or on their last legs before they reached the table top. Also, the ant chalk tests proved, Shih-Tzu’s love cheese savoury biscuits, ants do have jungle drums and at least six ants out of every ant colony are deaf.

Have you ever used ant chalk, and if so, did it work for you?

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© 2014, Martyn. All rights reserved.

13 thoughts on “Does Ant Chalk Really Work?

  1. Ah the loveable Thai มด “mot” (another word not for tinkering on Google with).

    I bought some flea/tick powder for the cat, works better on ants! The circle trick works great. Mind you it is local tick powder so its probably made from the Chinese “chalk” anyway!
    Mike recently posted..How to get Free Internet TV in ThailandMy Profile

  2. Hi Mike – The Chinese ant chalk does work but it’s best not to lick your fingers after using it. The chalk gets some ‘toxic’ write-ups on the internet. I wouldn’t apply any to a pussy… sorry, cat.

  3. Hi Mike, I live outside Phimai near Nakhon Ratchasima, I’m just on a UK home visit now.
    Yes,,,, it sure does work, and at a fraction of the price of the other types of ant powder. My wife turns it into powder by rubbing on one of my rasps (wood files) whenever she sees a new ant colony appear outside the house. Obviously you can’t just draw on the soil /dirt. Within half an hour there are NO live ants to be seen anywhere near the chalk. The obvious advantage of the chalk stick is that you can draw onto walls, anywhere you see them climbing in convoy.
    I didn’t realise it was banned from many countries as you said, so I must check up on the net to find out how dangerous it really is !!
    Thanks for an interesting post.
    Regards Ray.

  4. Ray – Thanks for the read and comment. If you follow the link in the post it points to an article about the toxic content of the Chinese chalk sticks. They’re not the kind of chalk to give a kid to play with.

    With the present weather in the UK you may need to unpack your rasp.

  5. Hi Mike, Thanks for your reply.
    Very sorry I didn’t realise there was a link waiting under the RED “ant chalk is toxic”
    I know my wife is unaware that it is dangerous, but then again some of the chemicals that get spayed onto our crops by the workers, whose only protection is an old tee shirt covering their faces, is very scary.
    Now I’ve read that link, it all makes sense. I guess I’m not as clued up on the computer as I thought I was.
    Many thanks again. Regards Ray.

  6. Ray – It’s quite a frightening read isn’t it. At least you are now aware of the dangers associated with the chalk. I’m glad to be of some help.

  7. Hello Martyn and Mike,

    Since the death of Google Reader last year my contact with all my old blog favourites has diminished, hence my relative unawareness of your continued activity in the blogging world. I use Feedly but it does not work at my workplace. Do you have favourite feed aggregators?

    Sorry Martyn for this hijack of the ants thread. Just train Tang Moo to lick up the ants with his tongue.
    Peter M recently posted..The Sleeping Dogs of Lumpini ParkMy Profile

  8. Peter – I use email subscription for the blogs I follow and for those I read from time to time I simply bookmark them and drop in whenever.

    The Juice is still active and hopefully will be so for a few more years yet. Hits are now on the up after its mauling at the paws of Google Panda. It was a totally unprovoked attack as well.

  9. Did a few experiments myself with just a stick of plain writing chalk, it’s obviously not going to kill them but they certainly don’t like to cross it. I’m a bit wary of using the ant chalk and other such pesticides for fear of ghekko’s being poisoned.

    I prefer to use an ant poison that goes by the name of ARS, it comes with a plastic container which the ants can enter but nothing else can. I’ve used them quite a lot and they are pretty effective.
    Darren C recently posted..Thailand Tourist BraceletsMy Profile

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