Question to the Department for Environment, Food and Rural Affairs:

To ask His Majesty's Government what assessment they have made of (1) the levels of fipronil and imidacloprid in bodies of water, and (2) the impact on those levels of routinely administering those substances to pets in the absence of flea infestation or risk; and what advice, if any, they provide to veterinarians about the use of those substances.

The Veterinary Medicines Directorate (VMD) leads the cross‑Government Pharmaceuticals in the Environment (PiE) Group and has published a roadmap responding to fipronil and imidacloprid detected in UK waterways. While the VMD does not undertake environmental monitoring of these substances, we liaise with the environment agencies that do, all of whom are represented on the PiE Group.

VMD‑funded studies show that topical spot‑on flea and tick products can contribute to environmental levels through wastewater pathways and when treated dogs swim.

Routine or preventive use may contribute to environmental inputs; however, there is no shared definition of risk‑based use across the companion animal sector. Prophylactic treatment may be appropriate in some cases, in the prevention of parasitic disease and zoonotic transfer, and the clinical justification for the decisions made by the attending veterinarian for such use is overseen independently of the VMD.

The VMD is funding research on how pet owner behaviours influence environmental outcomes to inform future communications and policy to promote responsible use. Alongside this, the VMD will launch national stewardship messaging in spring 2026 and is reviewing distribution categories to consider whether professional advice should be required at point of sale, helping protect both animal health and the environment.