Tseng Hsien-hsiung, who is president of the Mycological Society of the ROC, explains that "secondary metabolites" -byproducts of metabolism-secreted by fungi are powerful weapons which fungi use to defend themselves against their enemies. They include antibiotics, toxins, radioactive substances and even hallucinogenic chemicals, which is why many mushrooms and toadstools are not safe to eat.
深諳真菌優點的「中華民國真菌學會」理事長曾顯雄解釋，真菌分泌的「次級代謝物」，是真菌禦敵、自衛的最佳武器，它們包括了抗生素、毒素、放射物質，甚至具有迷幻作用的化學成分，這也是許多菇蕈不能任意食用的原因。