Bringing a new kitten home can be both an exciting and stressful time as you begin to acclimate to each other. If you have a kitten, it's important to feed it a balanced, nutritious diet appropriate to its age and to watch for any signs of health problems that might require treatment. 1. Upper Respiratory Infections Upper respiratory infections in kittens (sometimes referred to as cat flu) is a common ailment that can become very serious if left untreated.