thanks for the article wladek - good to know there is at least some potential issue or upper limit
that is a lot of garlic though - i make that equivalent to 3 large complete bulbs of fresh garlic - assuming 25g per bulb - per day for an 75-90kg adult
maybe this kind of dosing is possible with freeze dried garlic - but would still be some going
that said - usually rats and other rodents are much more tolerant of drugs/chemical than humans due to much faster detox processes ( some methods used in drug trials use a kind of rule of thumb of say 10-12x )
on the other hand - often other mammals have particular sensitivities to some plant compounds that humans do not have - eg dogs and chocolate - so i guess we cannot be sure
so the picture is less than clear - as is typical with herbs
i think there are at lease some reassuring studies of allicin in humans at the normally taken dosages that give some safety assurance - so perhaps its is other compounds in fresh garlic that have the hepatoxic effects?
this cell line study seems to indicate that there is a kind of dose dependent effect transition from undetectable levels of toxicity to significant at concentrations of allicin above around 0.03mM - which i think is well above therapeutic does used - but i haven't done the calculations on that
https://www.ncbi.nlm.nih.gov/pmc/articles/pmc5384165/there was also some mention of a reactive species flare initiated by garlic juice but not allicin - meaning that other compounds in Garlic Juice - apart from the allicin could be having separate toxic effects - which is interesting