Cooked or raw, onions are highly popular for adding flavor to many beloved dishes. Their history of powerful antibiotic capabilities makes me that much more likely to include them in my cooking this cold and flu season! Practically cousins to superstar garlic, onions contain sulfur compounds that have proven ability to ward off infection, even doing battle with resistant bacteria [source: Quigley].
Research has even examined the efficacy of onions against oral bacteria, and found that they are effective at managing bacteria associated with periodontal disease [source: Kim]. So add some raw onion to your sandwiches and chew thoroughly. You'll be doing yourself and your dentist a favor in the long run!