You cannot eat boletus for the same reason why you can’t eat oyster mushrooms in Australia, Japan and United States because they are filled with toxins. When you cook them at a temperature beyond 100 degrees Celsius, they will release certain enzymes that cause sickness to your system. Boletus is one of the mushroom that contains various chemical compounds like beta-glucan. In excess or even in normal amount it can cause problems to your body like nausea, headache and vomiting when it comes in contact with mucous membranes and blood. If you eat raw boletus then the risk for serious condition rises. Also most people who consume mushrooms experience no effects at all but some users still have symptoms after consuming wild mushroom such as feverishness, feeling nauseous, loss of appetite etc due to high level toxins or allergic reactions because their bodies are not used to those level of toxin exposure from wild mushrooms.