I'm sending you over to Dr. Mercola once again. He reports on using baking soda for colds and the flu. Apparently it was used back in 1917-18 for the Spanish influenza to good effect. I haven't personally tried this yet (I'm waiting til I can get some of Bob's Red Mills baking soda, which does NOT have aluminum in it).
If you're interested, read here. It's quite interesting, and if it works, then it certainly would be a great thing to have around.
You can get your Bob's Red Mills baking soda at some stores, or order online here.