Spot-on flea treatment typically comes in liquid form.
The treatment is applied directly to the skin of the dog, usually between the shoulder blades or along the back.
The liquid contains insecticides that are absorbed through the skin and into the bloodstream.
When fleas come into contact with the treated area, they are either killed or repelled.
The absorbed insecticides circulate within the dog's body, providing ongoing protection against fleas.
Some spot-on treatments also have additional ingredients to inhibit flea egg hatching and disrupt the flea life cycle.