In Jain Dharma, mushroom is generally not eaten.

Why not?

• Ahimsa: Mushroom grows in damp, decaying, earth-based conditions and is considered to involve more subtle living beings and higher harm than ordinary plants.
• Tamas / impurity concern: In traditional Jain dietary discipline, mushrooms are often grouped with foods avoided because they are believed to support violence and impurity in food habits.
• Root of caution: Jain food rules aim to minimize harm even to very small and subtle life forms. So mushrooms are usually excluded from a strict Jain diet.

Simple conclusion: A strict Jain should avoid mushrooms because they do not align with the principle of ahimsa and careful non-violence in eating.

If you want, I can also explain which foods Jains avoid and why in a simple list.