Cats can eat dog food in small amounts without immediate harm, as dog food is not toxic to cats. However, dog food is not formulated to meet the specific nutritional needs of cats, who are obligate carnivores requiring higher protein and certain nutrients like taurine that dog food lacks. Long-term feeding of dog food to cats can lead to serious health issues such as malnutrition, heart and eye disease, weakened immune system, and even organ damage. Therefore, dog food is not suitable for cats as a regular diet, but may be acceptable occasionally or in emergency situations when cat food is unavailable.