answer:To directly answer your question, certain chemicals in the mushroom make you “trip”. I don’t partake, but only certain mushrooms contain the chemicals that make you “trip”. These chemicals come from a specific group of mushrooms regardless of nutrient source, otherwise everyone would be having fun with their Portobellos that they fertilized with manure. I’m sure that psychedelic mushrooms can be, and are, grown with cow patties as the nutrient source, just like various other plants. Psychedelic mushroom wiki.