In Jain Dharma, mushrooms are generally not allowed to eat.

Main reasons (both Digambar and Shvetambar views are similar here):

1. Mushrooms are fungi (living beings)

They are not like regular vegetables. They are considered a separate life form, and eating them involves direct himsā (harm) to that life.

1. Grow in impure/decaying places

Mushrooms usually grow on moist, decaying matter and carry many micro-organisms and subtle jīvas with them. It is very hard to clean them without killing many tiny beings.

1. Linked with fermentation and micro-life

Like yeast and other fungi, they are connected with processes where countless one-sensed beings are born and killed. Jain food tries to avoid such items.

1. Actual practice

- In most Jain families and sanghs, mushrooms are kept in the same “avoid” category as: - root vegetables (potato, onion, garlic, etc.) - yeast and fermented items - So practically, Jains do not eat mushroom as part of Jain-acceptable food.

You can read a clear Jain explanation here