The problem is that pharmaceutical companies are the ones with the money to do the testing, and it isn't exactly in their best interests to find positive results. Scientific validation of herbals isn't free, and the two main sources of testing are the pharmaceutical labs and the universities who take large donations from pharmaceutical companies. The testing is often not so much 'double blinds' as 'double BINDS'. They can only patent NEW medications, they can't really patent medications based on herbs, and patenting and selling high-priced medications is what makes their world go round.
Not all antibiotics are created by man. Honey and aloe vera are two that I know of, and I'll bet there are more.
Sue
First, the herbal market is not small, it is a multi-billion dollar industry. By some accounts a 4 billion dollars a year industry. One would think the industry would be interested in scientifically valid testing by independent testing laboratories. But your right. They don't do their own testing. And yes, there is a profit motive. Word gets out that ginko doesn't do a thing for memory or brain function and it might take the shine off of sales of $14 bottles of ginko. As it has. Herbalists don't do scientific research for the simple reason that few of their products have any effect beyond what a placebo offers. If they had confidence in their product they would be financing their own independent testing and winning doctors over. Instead they wine and cry about how everyone is against them and all the scientists cheat.
The same effect doesn't really effect the pharmaceutical researchers. If they had found ginko worked they would have dug in deeper to find out exactly what compounds created the effect. They would then synthesize it, standardize doses in a easy to use package, and sell it. They would also work on finding out how the compound worked and improve on it.
But the simple fact is that despite ginko being used for hundreds of years people still suffer form memory loss and decline of brain function. Taking doesn't make any difference beyond what you would expect of any placebo. If a herb was truly effective it would rapidly be recognized as the definitive treatment of the disease and people would no longer suffer from the disease.
People had been fighting smallpox with all sorts of herbs and natural remedies. But nothing had any significant effect before vaccination. It was vaccination that wiped the disease out. You can go down the list of diseases we can now treat, manage, occasionally cure, and almost all of the diseases have been around for hundreds or thousands of years. Thousands of years with herbalists and witch doctors plugging away at them to little or no effect. It is hard to find a case where herbs have ever been a cure or completely effective treatment. The exception may be in nutritional deficiencies.
Finding out that natural quinine was partially effective against malaria led to purified forms of quinine. The understanding of how it worked led to chloroquine and the more modern forms. Quinine no longer does the job.
Neither aloe vera nor honey are antibiotics. They are topical anti-infectives. Mainly useful as a soothing agent for skin issues they have a limited effect in lowering the chances of infection. A mix of providone iodine and honey has shown some use in treating burns and some resistant skin infections.