From Drevan Harris in The Guardian:
In December the Veterinary Medicines Directorate (VMD) in the Department for the Environment Food and Rural Affairs (Defra) – which governs the use of medicines in animals – made clear that homeopathic treatments could only be classed as medicines, and thus prescribed by vets, if they were able to demonstrate efficacy.
Homeopathic products cannot demonstrate efficacy to any satisfactory degree and so this means that they can't be used by vets to treat animals. The use of homeopathy to treat animals – "there's no placebo effect in animals, is there, so it must work" the homeopaths claim – has long been a mainstay of the homeopathy industry's argument.
The logic of the VMD's decision is unquestionable. If it doesn't have efficacy, it can't be a medicine. And, ethically, if a medicine doesn't work then a sick animal deserves to have real treatment not sham treatment. The danger of course is that people may be lulled into believing a homeopathic remedy is actually treating their pets or livestock, when in fact a treatable disease is being allowed to get worse. This is avoidable harm – in other words, irresponsible behaviour or even animal cruelty.
The BBC report and the debate in the studio afterwards identified the obvious irony: that homeopathic medicines can't be provided by veterinary professionals to animals, but can be provided by healthcare professionals to humans – including those not able to make an informed choice, such as children and adults without the necessary mental capacity.