> If garlic is so obviously effective as the other commenter claims then there should be plenty of supporting evidence, it's not that hard or expensive to test

> If garlic is so obviously effective as the other commenter claims then there should be plenty of supporting evidence, it's not that hard or expensive to test for it, yet, this meta-analysis could only find a single good quality study that showed some effect. This line of reasoning is fraught with pitfalls. An inferred absence of True Scotsmen to use in an argument by authority doesn't prove a negative. Add that to the fact that there's a selection bias in favor of studies that appear to disprove commonly held beliefs (and generally almost no interest in studies that confirm them) and you really have to use more judgement if you're trying to get at the truth and not just win the argument. https://www.bmj.com/content/363/bmj.k5094 https://www.bmj.com/content/363/bmj.k5094