Giving Human Medicines to a Cat Can Be a Crime
UK: A couple, Susannah Self, 27, and Magno Sousa, 27, owned a cat and six kittens. The cats had the flu. They treated their cats with eyedrops and topical cream designed for humans with conjunctivitis. This was a crude attempt at a home treatment for a cat cold possibly caused by the herpes virus and a secondary bacterial infection.

Kitten maltreated with human medicine for conjunctivitis
They could not afford a veterinarian and in this instance a veterinarian was, in fact, the only option. One of the kittens lost an eye. They treated a kitten with a broken leg with Epsom salts. The RSPCA were tipped off and they paid a visit. They took the cats to a veterinarian to be examined.
The kitten with the broken leg was euthanised as it was decided he would not survive the operation. The couple were charged with three offences, I presume under the Animal Welfare Act 2006, and were convicted and punished by being banned from keeping animals for five years. Let this be a warning to wannabe home treatment fans.
The RSPCA say that they encounter a lot of cases were pet owners do not have sufficient funds to care for their animals properly which leads to home treatments. You have to be very knowledgeable to carry out effective and safe home treatments and ideally have a good relationship with a veterinarian.
It is well-known that cats are taken to the vets less than dogs. This is not because cats are necessarily healthier than dogs but because some cat owners are falling short in their duty to seek veterinary treatment when appropriate.
Also it is fair to say that too frequently cat owners have failed to grasp the extent of the commitment both financial and in time required to care for a cat. These assessments need to be conducted before adoption.
Source: lincolnshirelive.co.uk