There are many reasons your dog may be sneezing. These include allergy, kennel cough, infection, foreign body in the nose and tumor. With allergies, the sneezing will be seasonal, and there will be discharge from both nostrils. Kennel cough, which is often equivalent to a human cold, will include a dry, hacking cough and sneezing, but no other symptoms. As long as your dog's condition isn't accompanied by other symptoms and improves with treatment, you can try treating your pet with home remedies.
Especially in the case of kennel cough, a humid environment may help to ease some of the symptoms–especially the dry, hacking cough–your pet is experiencing. You can place a humidifier or vaporizer in the room where your dog sleeps. If you don't own a humidifier, run a hot shower and place your dog in the humid bathroom for a half hour. If your sneezing dog develops a dry, chapped nose, the humidity will also help ease the discomfort of this. You can also apply a bit of petroleum jelly to the end of your pet's nose.
Just like when people have a cold, dogs need extra rest while recovering from either allergies or kennel cough. Provide your dog with a warm and quiet place to sleep. Especially in the case of kennel cough, it is best to limit your pet's exercise. Exercise can trigger coughing in your pet. The dog should not be outdoors except for bathroom breaks. It's especially important for the pet to stay warm, dry and comfortable while ailing.
Just like when you have a cold, your dog's appetite may not be as strong as usual while the pet is suffering from allergies or kennel cough. Try warming canned food to give it a greater odor and stimulate your pet's appetite. Warmed chicken broth may be a nice treat for a dog that has a cold with an accompanying irritated throat. It will also help to get some extra fluids into your pet.
There are homeopathic, herbal and antioxidant remedies that may boost the immune system and help your dog recover from his cold more quickly. Echinacea is commonly recommended and is generally mixed into the dog's food for a week. Other herbs commonly used include licorice root, mullein, marshmallow and coltsfoot. Vitamins C and E may also be used for reducing any inflammation that accompanies the sneezing and to boost the dog's immune system.