Toadstools are known to us all, along with the fact that they are poisonous. Not many of us are aware that toadstools are actually mushrooms and not a different type of plant. In fact, toadstool is often used as slang for poisonous mushroom. Though there are some tell-tale signs that indicate whether a mushroom is poisonous or not, they may well vary for different varieties. So it’s always a good idea to stay clear of unknown varieties of mushrooms. Some signs that may be indicative of its poisonous nature are that the mushroom should have a flat cap that is devoid of any bumps while gills should be pink or black in color since mushrooms with white gills have often been found to be poisonous. Also the gills should remain attached to the cap instead of the stalk if it is pulled off. However, it’s extremely important to understand that the above rules may not be applicable to each and every type of mushroom and that those mushrooms whose origin is unknown is best avoided.