Pet owners could be banned from buying monthly over-the-counter flea and tick treatments in a bid to reduce their use, due to environmental contamination.
Ministers are considering restricting access to spot-on treatments and collars to prescriptions provided by vets and medical professionals only if there is an infestation of a pet's fur.
The move comes amid evidence the poisons are killing songbirds, which like to feather their nests with dog and cat hair, as well as contaminating rivers, killing aquatic life.
This is because the powerful toxins are water-soluble, so they easily wash into rivers if a dog goes swimming, and into water when a pet owner washes their hands after application.