ok im gonna break this down a bit because some of these are BLATANTLY untrue and it kills me every time i see this.
alcohol: not very good for humans, either, but alcohol effects pets the same way it effects humans: targeting the brain and the liver. the issue? it takes way less to kill your cat than it does a human. you weigh, on average, at least 100 pounds (or 10x) more than your cat does. 3 teaspoons of liquour could kill your cat. don’t do it. alcohol WILL poison your cat.
chocolate: theobromine (and to a lesser degree, caffeine) is the issue with this one. humans? we can break this down in our bodies. cats, dogs, birds, ferrets? they can’t. it usually takes a pretty big amount of theobromine to cause a pet to actually die, though. it’s present in cocoa, so the higher % of cocoa in a chocolate, the less needs to be ingested to cause serious, life-threatening effects. baking chocolate has a high concentration of theobromine and 1 square can kill a cat or small dog. white chocolate is a low risk, on the other hand. chocolate CAN poison your cat, especially DARK and BAKING chocolate.
caffeine: same story as alcohol: not that great for humans either, causes similar effects as in humans… just quicker and with less caffeine ingested. elevated heartrate, seizures, etc. can be seen. dogs and cats are more sensitive to the effects than humans are. caffeine WILL poison your cat.
dairy: cats are lactose intolerant and so their bodies cannot properly break it down– much like how we can break down theobromine and cats/dogs can’t. however, it’s not going to poison your cat, just give them diarrhea and other gastrointestinal upset. dairy WILL NOT poison your cat, but will cause gastrointestinal upset and diarrhea, so it is strongly recommended to not give dairy products to your pets.
fat trimmings: fat trimmings are just fat. if you feed fat to your cats, they will become fat and/or it will increase the level of lipids in the blood, leading to diseases and complications like chronic pancreatitis, which can be fatal. fat trimmings WILL NOT poison your cat, but will lead to disease that can be fatal, so it is strongly recommended to not feed fat trimmings to any pets.
raw meat: cats can eat raw meat. cats are obligate carnivores. cats are designed to only eat meat, and raw meat is not of serious risk to them. disease carried in raw meat? not a problem when you are a cat who has evolved over millions of years to eat raw meat. i hate hearing “cats can’t eat raw meat!” from people with outdoor cats. you realise your cats are eating raw lizard and bird, right? raw meat has more nutrients than cooked meat (which we eat veggies & fruits to compensate for– cats can’t digest these) and, obviously, there are some diseases and bacteria that cats aren’t immune to but cats are less likely to eat rotten meat than dogs are, anyway. treat the meat like you treat human meat and it’s totally fine. cats are DESIGNED TO EAT AND DIGEST RAW MEAT! IT’S PERFECTLY FINE TO FEED YOUR CAT RAW MEAT, but make sure that the meat is in-date and properly stored/cared for. rotten or spoiled meat CAN lead to disease and poisoning, but the same goes for 90% of the animal population!
eggs: its ok to feed your cat eggs. im not even sure why this is a question. raw eggs rarely carry salmonella and even humans rarely contract salmonella from infected eggs. your average cat will never contract salmonella from raw eggs, only in an immuno-compromised cat would this ever be an issue. cats can safely eat raw and cooked eggs, as salmonella is pretty much only a concern in an immuno-compromised cat in the first place.
fish: see raw meat above. fish, however, is a bit of an exception because of higher levels of mercury & low levels of taurine and differing balances of phosphate and calcium mean that it’s not a sustainable diet for cats and could lead to mercury poisoning or bone disease if it is the only protein given. when given ~1 time a week and with varied proteins there is no issue. again, cats are DESIGNED TO EAT AND DIGEST FISH AND OTHER MEATS! however, previous warnings about storing fish correctly still applies, and proteins should be varied due to fish having different levels of phosphorous, calcium, and taurine and mercury content. a primary diet of fish CAN lead to bone disease or mercury poisoning in extreme cases.
grapes and raisins: admittedly, this one is a bit of a wild card. some pets eat raisins/grapes without an issue, but in others, these can cause renal failure and death rapidly. we still don’t know why. animals with prior kidney issues are more likely to be effected by grape/raisin toxicity, and cats are more likely to have kidney issues due to many cats not getting adequate moisture in their diet. grapes and raisins MAY lead to poisoning in some cats and dogs, especially those with pre-existing kidney conditions.
onions and garlic: yes! all members of the allium genus (shallots, scallions, leeks, etc. are included) contain thiosulphate which, when ingested by cats and dogs, can lead to a serious condition in the blood known as hemolytic anemia. basically: their red blood cells burst. this can be fatal and a small amount of onion/garlic/etc. is needed to cause clinically significant issues. onions, garlic, and other members of the allium genus CAN and WILL poison your pet in even small amounts.
tuna: see fish above. canned tuna tends to be soaked in oil which leads to the same issues as fat trimmings in increasing lipid count in the blood. sashimi quality tuna will also have higher concentration of mercury and shouldn’t be consumed more than occasionally in the cat’s diet. canned tuna in oil is often too fatty and leads to the same issues as eating fat trimmings, however, tuna steak/sashimi/etc. quality tuna is the same as other fish: occasional inclusion in the diet is fine!
xylitol: relatively small quantities of this (an artificial sweetener) will cause a sudden drop in blood sugar in dogs, which can lead to comas, seizures, or death. many times, if they are not rushed to the hospital immediately, they will die, and even then, they may suffer permanent liver damage. however… cats are not adversely affected, and typically aren’t attracted to foods w/xylitol in it in the first place. xylitol is NOT likely to poison your cat, but small amounts can KILL your dog, moreso than chocolate!