Does your cat have bad breath? The odor that you smell is caused by an infection in your cat’s mouth. The most common cause of infection in your cat’s mouth is periodontal disease, which affects the majority of cat’s over 2 years of age. Of the cats affected by periodontal disease, half of them will develop painful resorptive lesions. Resorptive lesions cause destruction of the tooth below the gum line, hidden from view. Cats with periodontal disease may not show obvious signs of discomfort; they hide their pain well. Some cats may have foul smelling breath, chatter their teeth, and/or drop their food. Diagnosis of periodontal disease is made by close inspection of the oral cavity. Treatment of this progressive disease requires general anesthesia to clean and treat diseased teeth. After cleaning, all of the teeth need to be x-rayed so that hidden, painful resorptive lesions are not missed. Most teeth affected by resorption need to be extracted to remove the source of pain. Left untreated, periodontal disease causes chronic pain and infection. The oral infection can spread beyond the oral cavity to involve distant organs, such as the kidneys, liver, and heart. Cats need their teeth cleaned regularly just as people do. Home dental care and regular cleanings help maintain oral health.