People who are interested in “alternative” methods would probably be interested in solid, scientific knowledge regarding garlic’s antibacterial properties. It is said to be a “natural antibiotic,” but what does that really mean? Can it actually kill bacteria in the body, or just in a test tube?
I emphasize that this is a fantasy based on a single clinical trial, on top of one conducted on rats – under no circumstances should this be translated to the treatment of severe infections!
Quite recently there was a clinical trial that settled this issue:
It is true that only rats were tested, but such a clinical trial is still light years ahead of any “in vitro” tests, where you flood bacteria in a test tube with doses that are sometimes enough to kill an elephant.
The rats were infected with staphylococci, some susceptible to antibiotics, some resistant. The animals were given amoxicillin or garlic solution at two different concentrations; some received no drug and served as a control group.
As it turns out – garlic is an excellent antibiotic! But there is a catch here. First, the concentration must be high enough. And second, the effectiveness against antibiotic-resistant staphylococci was nil. A mixture of garlic and a normal antibiotic was marginally effective. For susceptible bacteria, high doses of garlic had efficacy equal to antibiotic therapy.
With animal trials, there is always the problem of converting units. The usual milligrams per kilogram of body weight often doesn’t work, because a rat’s body has a completely different metabolism and needs much more drug per body weight. But fortunately, we have the reported dose that the animals received. We know that a 50 mg dose of amoxicillin was equivalent to 400 mg of aqueous extract of garlic, 25% (w/v), which in turn is equivalent to 100 mg of garlic.
The resulting values are quite amazing, 1 gram of garlic corresponds to a normal, therapeutic dose of 500mg of amoxicillin!
The values seem downright unbelievable, I suspect a calculation error. Let’s check out a study that compared the effectiveness of allicin to antibiotics.
There they compared amoxicillin (along with a set of other drugs) at 2000 mg, and allicin at 1200 mcg. Well, that’s right – mg of amoxicillin is equivalent to mcg of allicin. The efficacy of allicin was quite a bit lower, but noticeable.
Here we have a comparison of the lethal dose of allicin and various antibiotics for different bacteria:
Admittedly, this is an in vitro comparison, but if the values are close to those obtained by calculation, then we can talk about confirmation.
Perhaps compare to the popular antibiotic, tetracycline. The dosage is about 1 gram per day. The bacteria-killing concentration was similar to that for allicin, which means that allicin should also be taken 1 gram. And this is already equivalent to 500 grams – half a kg – of garlic.
Amoxicillin is even more fun. It is two thousand times more lethal for bacteria than allicin. So in order to get the healing effect of 500 mg of amoxicillin, you need to take a kilogram of allicin. Two tons of fresh garlic.
But if we look at another study where they used identical criteria as above:
Garlic extract had similar lethality to amoxicillin! Not two tons anymore, but as much as amoxicillin alone weighs.
I’ll admit that I don’t know what to think about this. The differences obtained in various studies are on the order of six decimal places, some scientists gave a result several million times different
Here again, garlic extract was just as effective as antibiotics.
Here, in turn, half a gram of garlic powder had comparable effectiveness in humans in treating female organ infections as 250 mg of metronidazole.
Since one study gave results several million times higher than all the others, including the human clinical trial, I’m inclined to think that one should be discarded and the others left in. That is – consider that an 8 times higher dose of garlic extract corresponds to a given dose of amoxicillin. 4 grams of 25% extract corresponds to 500 mg (the classically prescribed dose) of the antibiotic.
Again, I repeat that these are fantasies based on one clinical trial and extrapolation of several others, giving up on treating your disease with antibiotics that have been tested in hundreds of clinical trials, based on this article, would just be foolish. At most, garlic can be used to try to deal with non-acute infections, or to support normal antibiotics when the infection requires them.
I think that if garlic was actually similar in efficacy to “normal” antibiotics, someone would have noticed it in the past, treating at least syphilis with it. After just one dose of penicillin the difference is striking, if one clove of garlic had the same effect it would be impossible to miss.