ALL pharmaceuticals are toxic if you take large enough amounts. Which is why the prescription, or the instructions on the bottle or package warn one not to take more that the specified dose.

Hell's bells, ANYTHING can be toxic in large enough doses. You can't live for more than a few days without water. But if you drink enough water at one time, it will wash all the nutrients and electrolytes out of your body and your nervous system will begin to malfunction. You will die if the electrolytes are not soon replaced. This is the whole purpose of such sport drinks as Gatorade:   to replace the electrolytes an athlete (or anyone else) loses when he or she sweats like a pig during strenuous activity.

Oxygen. Absolutely essential if we are to live for more that a few minutes! But if you spend more than a few minutes in a 100% oxygen atmosphere are the normal atmospheric pressure of 14.7 psi., you will die of oxygen poisoning.

There is an ongoing investigation about a possible connection between certain vaccines and the incidence of childhood autism, but as yet, there is no real evidence of a causal connection. But in general, this wheeze about vaccines being poisonous has been around since the time of Jenner. Yet many dreaded diseased that used to obliterate people by the tens or hundreds of thousands have all but been wiped out since the advent of vaccines.

Rationality and science march on. Stupidity and superstition also seem to march relentlessly on, and it's a perpetual race to see which will win.

Don Firth