What's the quickest way to get a laugh out of your doctor? Mention herbal remedies.

But while he's laughing and dismissing these centuries-old treatments as "folk medicine," researchers on the cutting-edge of modern science have found at least eight common plants that can kill infection-causing bacteria and fungus.

And you might even have some of these living miracles growing in your own garden right now.

Indian researchers set out to test these ancient folk remedies against tough bacteria and fungi by collecting samples from the mouths of 40 oral cancer patients.

They chose cancer patients because these people often have compromised immune systems and are especially vulnerable to bacterial and fungal infections -- and, sure enough, tests revealed that 35 of the 40 had low white blood cell counts.

Then, the researchers let those samples grow in the lab and arranged individual battles: In one corner, brawny bacteria and frightening fungi... in the other, asparagus.

Yes, asparagus. Wimpy, green, pee-stinking asparagus.

And you're not going to believe what happened next: Asparagus won.

In fact, the researchers say eight of the garden-variety extracts they tested worked as broad-spectrum antibiotics. They say extracts from wild asparagus, desert date, false daisy, castor oil, curry tree and fenugreek laid waste to bacteria such as E. coli and S. aureus and fungi like Candida and Aspergillus.

What's more, the researchers wrote that two of these extracts -- desert date and castor oil -- were able to wipe out Pseudomonas aeruginosa and other bacteria that are notoriously tough to beat with regular antibiotics.

And that gives scientists hope that plant extracts may turn out to be the answer for multidrug-resistant superbugs such as MRSA.

Of course, the study in the Annals of Clinical Microbiology and Antimicrobials is just a lab-dish experiment and not a clinical trial -- no actual infections were treated or cured.

But the researchers say they plan more tests -- including clinical ones.

And if those pan out, maybe your doctor will stop laughing next time you mention herbal remedies.

Maybe... but I doubt it.