You can't get past the first page of any toxicology text without reading Paracelsus's decree: "The dose makes the poison" and that is certainly never more true than with Botox. One of the most toxic poisons, far more deadly than any synthetic toxicant, properly diluted has numerous benefits, with additional uses now being reported.
So how come microbiologists seem immune to the decree? They love to report that there is e.coli/salmonella/campylobacter... in food and that you therefore should trust them when they say don't eat it and thank them when they save your life. Doesn't the concept of an LD50 exist in their profession? Or is it really all about fearmongering?