Pouring a bottle of apple cider vinegar over your pet will not magically make fleas disappear—so don’t try it. However, there are multiple ways this natural flea repellent can be used: in drinking water, in baths and as a spray.
If you choose to use apple cider vinegar to bathe your pet, using a diluted solution is best. This option can be used as a preventative or a treatment, depending on your needs.
Adding apple cider vinegar to your dog’s drinking water can be a good option, but it may be a little tricky, explains Matheson. For this option you should include a teaspoon of apple cider vinegar for every quart of water, but your dog might not be a fan at first. You may have to introduce this gradually because apple cider vinegar does have a distinct taste.