Question: are mushrooms with white gills poisonous?
Answer: If the gills are white then the mushroom is possibly poisonous. The cap and gills of the The Destroying Angel, the Spring Amanita, the Clitocybe Dealbata and the Clitocybe Rivulosa (right) are all white, and all are deadly. So a white mushroom with white gills is generally something to avoid.