According to Vetinfo, vitamin C, elderberry and licorice root are helpful natural remedies for a cat with a cold. The Nest recommends l-lysine for colds caused by viruses as well as saline nasal drops to relieve symptoms. Cat owners must determine the cause of the cat's cold to choose proper treatment, since some more serious diseases cause symptoms similar to cold symptoms.
As Vetinfo points out, vitamin C boosts a cat's immune system and energy levels, giving the pet the ability to fight off cold infections. Taking vitamin C can also shorten the duration of a cold. Elderberry made into a tea and licorice root soothe a cat's mucus membranes, bringing relief to sneezing and runny nose symptoms.
As The Next explains, administering saline nasal drops helps open up a sick cat's nasal passages. If the cat's cold is caused by a virus, 250 to 500 milligrams daily of l-lysine provides relief of cold symptoms and speeds up recovery.
According to WebMD, however, cat owners should be aware that colds often display symptoms very similar to feline viral rhinotracheitis, which is caused by feline herpesvirus 1. This disease, which can become chronic and cause permanent damage to the cat's eyes, must be treated by a veterinarian. Vets are likely to prescribe antibiotics and, in extreme cases, insert a feeding tube to make sure the cat stays hydrated and fed.