At least 11 people have died from the effects of the fungi and hundreds more have been hospitalised.
There is no effective treatment for this kind of poisoning, Iran's Tasnim News Agency reports.
At least two people have received liver transplants. The mushrooms concerned look similar to edible ones.
People have been urged not to buy loose mushrooms and only purchase those packed and sealed in shops.
According to BBC Persian, mushrooms can sometimes be seen for sale in the street in Iran, and local folk wisdom about which ones are safe to eat can be unreliable.
The deadly fungi grow wild in mountainous regions of Iran's west after spring showers, according to Tasnim.
Seven of the dead came from the Kermanshah area.
Reports suggest that unprecedented rainfall over the past month has led to more mushrooms growing than usual.
