Public health permanent secretary Narong Sahametapat yesterday said wild mushroom species, including edible and poisonous ones, were abundant during the rainy season.
Some poisonous species looked edible. People would pick the mushrooms for cooking only to fall ill after eating the poisonous types, he said.
The Epidemiology Bureau received reports that 91 people across the country have fallen ill.
However, no deaths were reported.
So far, 22 provinces have submitted their reports on the number of people who have fallen ill. Phangnga had the highest cases of poisonous mushroom consumption at 23, followed by Chiang Rai with 20, Khon Kaen with five and Si Sa Ket, four. Most patients live in rural areas.
The number of sick people is expected to increase by 4-5 times during the rainy season.
Last year, 1,381 people across the country fell ill after consuming poisonous mushrooms, said Dr Narong. Of those people, three died.
Disease Control Department chief Sophon Mekthon said most cases involved consumption of 12 wild mushroom species, including hed ra ngok hin (Fool's Mushroom), hed samong wure (Brain Mushroom), hed hing hoi (Inky Cap), and hed kled dao (Panther Cap).
Dr Sophon said hed ra ngok hin was the most poisonous species as it can cause death within 4-10 hours. It contains amatoxins and phallotoxins, chemical compounds that could destroy the liver, kidney, brain, blood and respiratory systems. It poses a danger even if it is cooked.
Early symptoms of mushroom poisoning include headache, vomiting, stomach ache, fast heartbeat and abdominal cramp, said the department chief.
Poisonous mushrooms were found every year between January and April, said Dr Narong.