[greenbean36191]

The sources in the wikipedia article and the next two articles cited are based on in vitro work using either refined allicin or various preparations of garlic extract standardized for allicin. Not even the antimicrobial effect has been demonstrated when the garlic is administered orally in vivo. In fact, it can't even be detected in the blood when it's administered orally.

The rest of the quotes are anecdotal or vague mentions of what someone else claimed. We already have plenty of anecdotal evidence suggesting that garlic is an appetite stimulant, parasite treatment, or immune booster. The problem is that anecdote is notoriously unreliable. It's especially unreliable in the case of ich treatments because the parasite naturally drops off and often doesn't reinfect at visible levels again, even without treatment. There's lots of anecdotal evidence that shark cartilage prevents or treats cancer too- something that controlled tests just don't support.

We don't have any controlled tests confirming that feeding garlic in vivo actually confers the benefits people claim or that are seen in vitro. In fact we have evidence that the effects people see don't occur by the suggested mechanism. That certainly doesn't mean that garlic doesn't work, but it's far from a proven cure. A lot more work needs to be done.