McTavish who chews cardboard! c. Pat Caullay

Cats that start eating strange items, such as their cat litter, should be checked by a vet. It can be a symptom of illness.
Some cats seem turned on by plants or household items, such as valerian, both growing and dry, herbal teas, and Flash liquid floor cleaner! Jumpers, a tortoiseshell from Yorkshire is turned on by her owner's roll-on deodorants, all makes! The cat will do a lot of sniffing and maybe some licking, and may show signs of silly druggy behaviour!
Next there are cats that eat strange substances like cardboard or wool, cats who chew and rip but don't eat and cats that just lick these odd materials. Again, it is important to check with the vet, because some of these behaviours can be a sign of physical illness.
But eating strange things like wool or cotton can also be a disorder of the cat's natural hunting behaviour which is to stalk, pounce, tear off feathers and skin, and eat. Not only does skin and feathers pass through the cat's stomach, but the cat has an instinct to do the tearing and plucking before swallowing.
Some pet cats get compulsive about this part of the predatory sequence - tearing off feathers and skin bit and swallowing it all. Since ordinary cat food gives no chance of tearing and ripping, the cat looks for this somewhere else. They will tear and rip and then eat -- wool, cotton, paper, cardboard, wicker baskets, electric cables. Some cats go out and steal soft toys, bring them home and tear them - imitating the whole hunting sequence with teddy-bear prey!
The danger from eating wool etc is that they will get an internal blockage. One Burmese had seven stomach ops to get rid of blockages caused by eating tea cloths and woolly jumpers.
These wool eaters (often pedigree breeds kept indoors without a cat flap) need help urgently. Experts used to suggest feeding high fibre food, gristly meat, and frequent meals in the hope that this would make the cats feel their tummies were full and they would have lots of chance to chew.
But now they suggest supplying something closer to nature -- something for your cat to tear and shred. Peter Neville, the expert on this behaviour, suggests getting dead whole turkey chicks, day-old chicks or dead whole rats sold frozen by pet shops for reptiles. If these aren't available try the frozen dead mice. Or, if all else fails, see if you can buy hens with their feathers still on from a local farm shop.
These should be the cat's main diet, eaten in a room like a bathroom where blood won't get on the carpet! If you want to add a little dry food on top of this (only a minority part of the diet) do so in a foraging toy, where the cat has to work to get the dried food out. A vitamin supplement designed for cats and fed in the right quantities would do no harm.
Although the whole idea is disgusting to humans, these may be the only way you can cure your cat of what may be a dangerous disorder. Cats who have been wool-eating for only a few months often recover completely on this diet. Cats who have been wool-eating for years may occasionally wool-eat. Give it a month before you decide it hasn't worked; sometimes it takes a bit of time for the cat to realise it doesn't need to eat wool.
It is also important to try and give the cat the chance to hunt! Most wool-eaters are indoor cats, so get a fishing rod toy or just a piece of string , and try to give the cat 30 pounces on this every day. NEVER breed from a cat who eats wool - it may be a hereditary disorder.
It is always worth checking whether the cat's environment can be improved, since it may be that stress plays a part in triggering this disorder. Stress can be caused by boredom, anxiety about cats outside, anxiety about cat companions, changes in routine, moving home etc. Read: EIGHTEEN REASONS WHY YOUR CAT FEELS STRESSED AND UNHAPPY - AND WHAT TO DO ABOUT THEM.
If you do think there is something that triggers the cat to eat wool, start keeping a diary to see if it really is a trigger or not. Armed with this information, contact a pet behaviour counsellor.

NOTE ON SALMONELLA
Day old chicks, mice etc. or any uncooked meat can carry salmonella so wash your hands after handling them, and do not let your cat lick round your mouth or hands after eating them. The risk of feeding them is probably no more than the risk that your cat might pick up a salmonella bug from mice or birds, but if you think your cat is ill, call a vet. Immuno compromised or pregnant humans or cats should take expert advice before feeding this diet.