From Green Dog Pet Supply:
I thought I'd give you all a quick heads up - it seems there is a bit of an outbreak of kennel cough here in the Portland area. I got a call last night from the good folks at Doggy Business, letting us know that though they have only received about 4 reports of kennel cough in the last few days from customers, there are a few daycares here in town that have actually closed temporarily to help to slow the spread of the disease. Doggy Business is being vigilant and notifying their customers to ensure that people are watching for signs. Kennel cough, or Bordatella, is a generally mild, though very contageous respiratory illness that can be caused by bacteria, flu-like viruses, or a combination of both. Immunization cannot prevent all occurrences of kennel cough, so even if they've had the immunization, they still could fall ill if interacting with another dog that is shedding the virus. The most obvious symptom is a dry hacking cough, and sometimes some lethargy. In rarer cases it can evolve into pneumonia, so if your dog seems to be getting sicker (poor appetite, listlessnes, or fever), do see a vet.
If it's just a cough, keep them out of the daycares, classes, and parks for a while
here are a few useful links to learn more:
http://www.peteducation.com/article.cfm?c=2+2102&aid=452
http://www.marvistavet.com/html/kennel_cough.html
To soothe the coughing, we have a tincture called phytomucil that is useful for soothing coughs. Or, you can go to the Whole Foods bulk spice/herb section and pick up either marshmallow root or slippery elm. Bring it home and make a tea from it (a spoonful of root to a big mug of water), let it cool and offer it to your pet. These herbs are both useful for soothing the throat, are very safe and are both kind of sweet, so usually liked by dogs - you could also put in some chicken broth if they won't drink it straight.
I read an interesting thing online that I haven't tried - making a concoction of 8 oz water, 3 drops of hydrogen peroxide, and one teaspoon of honey in warm water. I have no experience with this, but I see lots of testimonials here. The part of it that I like best is the honey, which is both soothing and has antibacterial properties.