I'm not sure what you mean by this. By 'natural toxins', do you mean allelopathic chemicals? Or do you mean the toxins that exist in many of our plants?

I'm with rhizo on this one. It sounds like you're asking if the mushrooms will take on the characteristics of the surrounding plants and/or food sources you feed it. Mushrooms grown in banana compost do not smell or taste like bananas, they don't even have higher potassium concentrations than if they were grown in more traditional mediums.

Sorry about that. Let me be more specific. I am growing Caster Bean plants. I think ( but not positive ) that the roots also contain some of the toxins found in the beans. The spot that I am growing one of the beans in is near where a mushroom bed was going to be. There is also another weed that grows next door that drops poisonous berrys in my yard so I was wondering if there was a source that would be able to answer whether or not a specific type mushroom would absorb the toxins. I have been told that some mushrooms concentrate toxins in their bodies while others dissipate them. I dont know the facts so I was asking if anyone here knew these answers or a source I may refer to.

Thanks