When a cat is very satisfied with its current situation, it will make a vibrating sound through its vocal cords. The owner can stroke the cat's head and back, which will make the cat more comfortable. If the sound continues and the cat's condition is abnormal, it may be a disease. If caused, the cat should be sent to the pet hospital immediately for examination and treatment. During this period, the cat's diet should be adjusted, and the cat's living environment should be kept clean and hygienic to reduce infection.