The inexpensive herb milk thistle is known to protect against amanita poisoning.
Yes but the flavanoids from milk thistle are not sufficiently absorbed enough by themselves and it must be delivered intravenously.
“However, an intravenous preparation of milk thistle extract has been available in Europe for over 20 years: Legalon SIL. This GMP-manufactured product is common to emergency rooms in Germany, France, and Belgium for the treatment of mushroom poisoning. The preparation is comprised of silybin A and silybin B – known collectively as silibinin – as a hemisuccinate that both improves the solubility and bioavailability of the compounds.”
https://sciencebasedmedicine.org/milk-thistle-and-mushroom-poisoning/
I'm a mushroom picker so I'm very aware of the potential hazards involved. And yes, there are hazards but frankly, only if you're dumb enough to take chances. Follow this one rule and you'll never go wrong: Never eat a mushroom that you have not 100% identified as being edible. Not 99%, not 99.99% but ONE HUNDRED PERCENT.
I have a few other rules but that's the only one that really matters. One of those is this one: Never pick pure white mushrooms with white stipes and white gills they're too difficult to 100% identify. Many of them belong to different families, some of them are poisonous and a few are as deadly poisonous as the Death Cap.
Fun Death Cap poisoning fact: One of the reasons the poison is so deadly is because your liver and kidneys cannot get rid of it. It just circulates through the liver and kidneys, slowly destroying them. Milk Thistle helps precipitate it out and currently is the only antidote that is effective, if you get treated with it shortly after ingesting the shrooms. If not, you will die - unless you can get a liver and/or kidney transplant(s) in time.