Did you ever wonder why bacteria are able to develop resistance against antibiotics like penicillin in a few decades, but seem to be powerless against more natural cures like honey and tea tree oil? Honey has been used as a topical antibiotic since the time of ancient Egypt, yet it seems to be just as effective now. Tea tree oil has been used for 1000 years by aboriginal Australians. Now it is being studied as a therapy for multi drug resistant Staph infections. Every year tea tree leaves fall to the ground for as long as tea trees have existed. Remember, we discovered their anti-bacterial properties 1000 years ago. Tea trees have been around far longer. And in all that time, bacteria never built up resistance. Vancomycin, the antibiotic of last resort was first isolated about 60 years ago, yet bacteria are already building up resistance.
This raises several questions. Why should modern antibiotics become useless in a matter of decades? The answer is rooted in the fact that most antibiotics are derived from fungi. Bacteria and fungi have been scrapping back and forth for about a billion years. A billion years is plenty of time for fungi to develop all sorts of toxins. Bacteria, for their part, have evolved all sorts of strategies to combat those toxins. Many defenses are coded into their DNA. Once exposed to a new antibiotic, it is a simple thing for the bacteria to adapt.
Essential oils are a much different beast. Flowering plants which produce essential oils have only been around for about 75 million years. Despite their dominance today, they are newcomers on the evolutionary time scale. Bacteria have had less than 10 million years to fight with many oil bearing plants we have today.
Why are such effective products not more widely used then? There are several reasons. The first is money. There is no incentive for pharmaceutical companies to run the expensive clinical trials needed to get essential oils approved by the FDA. There is nothing to patent, no way to make back the investment in R&D. It is a paradox that everybody knows lavender is a good antibiotic and anti-inflammatory, but no governing body is willing to approve it for these purposes. Centuries of use do not take the place of placebo controlled, double-blind clinical trials in the eyes of the FDA.
In addition, there is a revolving door between the FDA and the pharmaceutical industry. This does make sense. We want people familiar with the drug discovery and approval process to regulate it. We want a "safe and effective" drug supply. The public does need to be protected from medicines with unsubstantiated claims. Unfortunately, these regulators have developed a sort of tunnel vision based on their experience with synthetic drugs. There are side effects, sometimes life-threatening. Toxicity trials need to be run. Drug metabolism and disposition studies must be run. A full suite of analytical methods must be developed and validated before we can allow a drug on the market. Essential oils do not fit into this template very well. They really don't need this level of scrutiny because they are natural, not synthetic. From an evolutionary standpoint, they "grew up" with the forerunners of the human race. They are intrinsically more compatible.
There is also the hubris of the modern medical community. As late as 1970, scientists were proclaiming bacterial infections would be a thing of the past by 2000. Humans had conquered the lowly bacteria through their superior intellect and technology. The days of poultices and tinctures were over. We had made a drug to kill every bug...
But our "wonder drugs" were based on their ancient adversary- the fungus. Like a veteran baseball player facing the hotshot rookie pitcher, bacteria quickly figured out how to send these rookie drugs back to the locker room.
There is a body of evidence out there. Studies have been done usually sponsored by some government. There is a really good book on the topic, "Herbal Antibiotics" by Stephen Harrod Buhner. The mainstream medical community does not embrace them, nor would I ever expect them to. Essential oils are a square peg in a world of round holes to them, something primitive people use.