Cats have shared a long history with humans, dating back more than 9,000 years. Originally drawn to human settlements by the presence of rodents, cats became valuable for controlling pests, especially in farming communities. This relationship helped solidify the image of cats as creatures associated with milk, as before the rise of commercial pet food, they were often fed food scraps from the family table. In his 1877 book on cats, Scottish doctor Gordon Stables suggested that cats need two bowls—one for water and the other for milk—and recommended porridge and milk as a good breakfast. This idea helped create a widespread belief that cats and milk are naturally compatible, a notion reinforced by countless appearances in art, literature, films, and cartoons, including the familiar image of a street cat being rescued with a saucer of milk. However, modern research has shown that cats should not be given milk at all. Most cats are lactose intolerant, meaning they lack the enzyme lactase needed to digest lactose, a sugar found in milk. Like all mammals, cats begin life drinking their mother's milk, but after weaning—usually between 6 and 12 weeks of age—kittens stop producing lactase. This means that for most cats, milk is not necessary and can actually lead to digestive problems. The severity of these issues can vary depending on how much lactase a cat's body naturally produces. Cow’s milk, in particular, is not suitable for cats, even as kittens, because it contains much more lactose than a mother cat’s milk. It is best for kittens to drink from their mother or to be given a specially formulated kitten milk replacer. Additionally, some cats may develop allergies to milk or dairy products, which can cause more severe reactions. When cats consume milk, the lactose cannot be broken down and absorbed, leading to digestive issues such as gas, bloating, constipation, abdominal pain, and sometimes nausea or vomiting. The most common and concerning symptom is diarrhea, which can lead to dehydration, electrolyte imbalances, and in severe cases, even be life-threatening. Cats may be attracted to milk because it contains proteins and fats that are highly appealing to them, especially since they require high levels of protein and fat for good health. Cow’s milk also contains casein, a protein that may have a calming effect on some cats. However, despite these attractions, milk is not a natural part of a cat's diet and can cause discomfort and health problems. While some people might think of milk as an occasional treat, the general recommendation is to avoid it entirely. Even lactose-free milk or specially formulated cat milk offers no real nutritional benefit and should only be given very rarely. Alternatives like oat, soy, or almond milk are also not recommended, as they can cause digestive issues. In summary, cats do not need milk, likely cannot digest it, and it is more likely to cause harm than provide any benefit.