Originally Answered: What home remedies can I use on my cat that keeps chewing off her fur?
There are a couple of reasons your cat could be over-grooming:
1. Dermatitis - if she has a primary skin problem, like a staph infection or ringworm, she will itch and overgroom. This cannot be treated effectively with home remedies, but thankfully is not as common as other causes.
2. Food allergies - fairly common in domestic animals. Grains and chicken are the most common allergens. Cats do not need grains in their diet, so try introducing a diet based on a protein that she's never been exposed to (duck, venison, rabbit, kangaroo, etc). Animals develop food allergies after prolonged exposure, so it's very possible for her to be allergic to her food if she's never had a problem with it before. Some cats have sensitive GI tracts, so you may want to switch her over gradually. It can take 1-2 months to see improvement with food allergies.
3. Flea allergies - VERY common in cats. If she is not on effective flea control, you should consider that a highly probable source of itching. The best flea medications are prescription through your vet. Be careful if you decide to use non-prescription products on your cat. Anything with permethrins, pyrethrins, or chrysanthemum extract is TOXIC to cats and will cause neurological damage. Check labels carefully and never use dog products on cats. Flea allergic animals often groom away fleas so effectively that you never see the fleas. If she is not on flea control, try it before deciding that she doesn't have any on her.
3. Environmental allergies - unfortunately cats can also have environmental allergies just like people. These are harder to handle as there isn't a good way to prevent exposure to most of the allergens: pollens, mold, etc. There are medications to reduce sensitivity, but most vets will only prescribe them after ruling out all of the other causes, as they have side effects like damping the immune response.
4. Stress - it is not uncommon for cats to have "psychogenic alopecia", which is basically neurotically grooming themselves to the point of having bald spots. Some cats do this in response to a specific stressor, which you may be able to discover and eliminate. If there is tension between her and another cat in the household, that could also cause this problem. Other cats develop this out of boredom. If you are seeking a way to eliminate boredom, there are a lots of neat tips and tricks to be found through Google as "Enrichment" or "Homemade toys" for your cat. Playing with her or setting up problem solving games may give her something to do and reduce her stress.
I would like to encourage you to try to suss out the root of her issue before just trying to make her fur taste bad, as she may have a real problem that is causing her to act this way.
To the individual who for some reason believes that veterinarians are in a conspiracy with food companies I can only say this:
I can tell you that as a vet student my course on nutrition was taught by a veterinary nutritionist who was board certified in veterinary internal medicine, not a pet food rep. Our gastroenterology course was also taught by an internist. No one has ever taught a medical or nutritional course to us who was not a doctor, either in veterinary medicine or a PhD in a related field. They were all employed by the university, not pet food companies.
I can also tell you that while working in the veterinary hospital we never marketed the food we had available or pushed food simply because of a "deal" with pet food companies. We frequently recommended foods that we did not carry and recommended that clients their own judgment and preference in selecting foods.
I know that, as in all things, there are clinics who are swayed into over-recommending specific brands, but it is not a universal practice. There is also currently a great deal of effort in the veterinary field to standardize and police the relationship between clinics and food/pharmaceutical companies, so that the best health care is offered without bias.