I've browsed far and wide for home remedies for an indoor ant problem. Whenever vinegar or rubbing alcohol are mentioned, the instructions always say to cut them with water and sometimes dish soap. Can anyone explain the purpose of that? Why not spray the straight 100% vinegar/alcohol?

P.S. Context: This is a rented 1-bedroom apartment on the 9th floor of a highrise, so many outdoor ideas are not applicable. I suspect that many ideas about modifying the unit or blocking outdoor entry don't apply.

P.P.S. More web searching reveals that vinegar repels ants, but doesn't hurt them. I find this odd, as straight uncut vinegar is acidic. I'm wondering about the veracity of the claim that vinegar is not harmful to ants. Would someone with expert knowledge be able to sine some light on this?

P.P.P.S. Disturbing observation today: Undiluted vinegar doesn't even seem to repel my ants. I sprayed some droplets on the counter top so that I can prepare food with some peace of mind. Lo and behold, ants were traipsing about the droplets. Isn't evolution a marvel?

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    I don't have expert knowledge, but acetic acid is a weak acid, and is also diluted to 5% strength when you buy it as vinegar. If it doesn't harm ants, it's probably because it dries before it can do any damage. It will also burn your skin if you leave it on long enough, but it normally dries before that happens.
    – piojo
    Sep 16, 2019 at 3:42
  • OK, so your hypothesis is that vinegar isn't used for its acidicness, but rather, its smell. Could very well be. Thanks! Sep 16, 2019 at 5:04
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    Correct. Also, unless you give the ants a bath, it will only touch the lower parts of their feet, and maybe their antennas. Even if it caused some damage there, it might not be enough to disable the ant.
    – piojo
    Sep 16, 2019 at 5:06
  • @piojo: why don't you make that a proper answer, so we can vote? :)
    – virolino
    Sep 16, 2019 at 10:41
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    Hi @user2153235! I'm one of the site moderators on Lifehacks SE. Generally, questions like this are off-topic because they're asking about an existing lifehack, instead of asking users for a clever solution to a common problem. Questions here are almost always in the form of, "What's a natural way for me to kill ants, without chemical pesticides?" However, I'm a new moderator, and there's a fine conversation going on in the comments, so I'll see how the other members and moderators want to handle this. Sep 16, 2019 at 15:14

2 Answers 2


When vinegar and water is used, the recommendation is to coat the entire surface in the vinegar/water solution. As you observed, when you spray vinegar, it does not form a continuous coat but separate blobs that the ants can navigate between.

Adding soap reduces the surface tension and allows the mix to spread out more.

I suspect the recommendation is to cut with water to prevent damage to the surface you're using the mix on. You don't need a highly-concentrated mix, you're just disrupting the pheromone trails left by the ants - and those scent markers are tiny so you don't need much to disrupt them.

  • Thanks Hobbes. I'm wondering if you can clarify something about the proposed explanation. I thought that the vinegar's smell was disrupting the ability to detect the trail, so shouldn't it be effective regardless of whether the physical liquid vinegar actually covers the trail? I mean, if the trail needs obliteration or obfuscation, then even wiping with a damp cloth will do that, and vinegar is not required. Sep 17, 2019 at 23:29
  • This is just guesswork on my part: the vinegar will break down the pheromones - but to do that it has to be in contact.
    – Hobbes
    Sep 18, 2019 at 8:59
  • Thanks for clarifying. I marked "up" the answer, but I'll let a biology expert say whether or not it is correct. Sep 19, 2019 at 0:56

Title: Spray alcohol, feed. The end!

A spritz of rubbing alcohol will instantly kill any insect. Plus, because alcohol is a disinfectant, there is no need to rinse. The alcohol simply dries up in a minute or two. So after you have killed the trail of ants by spritzing the alcohol from you spray bottle; lay down a mixture of borax and sweet-smelling maple syrup to kill the ant nest.

Here’s how: Put a sprinkle of borax on a formed piece of tin foil the size of your thumb ... then squirt 1 tsp. of the maple syrup in the middle. As the ants track over the borax they are poisoned. Then after they eat the syrup they go back to the colony with their "take-out" special for all the rest of the colony and Queen to eat. After a few days … no more ants because everybody dies.

(One final tip about the spray of alcohol. It will also kill flying nats, miscotos, house flies, and more ... they fall right out of the misty-fog-spray of your spray bottle.)

  • Thanks, Mark. I done something along the lines of Borax. Commercial ant traps, with openings into a container filled with fluid, likely Borax based. It had a temporary effect. Over the course of the past 3/4 of a year, the high rise management has had a pest control company visit, dabbing drops of goo which is likely to be borax-based. Always, limited effect. It's the trade-off of living in a high rise. The colony could be quite far away, and the chances of the stuff in my unit affecting their queen depends on proximity. Aug 2, 2020 at 23:10

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