False morels (Gyromitra esculenta) are one of the most common Estonian springtime mushrooms and are especially widespread in sandy pine forests. The false morel has an irregular-shaped, convoluted and twisted cap which resembles the human brain. Even though poisonous when eaten fresh, it is a great edible mushroom if parboiled. Toxins are volatile in case mushrooms are boiled in a pot or fried in a pan without a lid, but not when heated in a microwave. Mushrooms should be boiled in a well-ventilated room and windows should be open since even the vapour is toxic. The water in which the mushrooms were boiled or rinsed should definitely be disposed of and must not be used for drinking or during cooking.
Eating uncooked mushrooms causes gyromitrin poisoning which damages the liver, central nervous system as well as sometimes kidneys and may even be fatal. Symptoms include vomiting and diarrhoea, later on also dizziness, lethargy and a headache.
About this stamp in philately foorum.