The mucus that appears like a runny nose in a cat may be caused by gastroenteritis, improper diet, indigestion, internal parasites, feline distemper, or hairball syndrome. First, observe whether the cat is still vomiting or in poor spirits. , loss of appetite, etc. If there are any abnormalities, it is best to send them to the pet hospital for examination and treatment. If there are no abnormalities, you can feed the cat some probiotics and cat grass, adjust its diet, and regularly deworm the cat.