In Jain Dharma, onion is generally not allowed for two main reasons:

1. It is a root vegetable (mūl-ki sabzi)

- Onion grows inside the soil. - To remove one onion, the whole plant is uprooted. - This kills: - The main plant - Many tiny living organisms (jiv) in the soil - This goes against ahimsa (non‑violence), which is the highest principle in Jainism. - For this same reason, Jains traditionally avoid potato, garlic, carrot, radish, etc.

1. It disturbs the mind and increases passions

- Jain Acharyas explain that onion–garlic type foods: - Increase krodh, maan, māyā, lobh (anger, ego, deceit, greed) - Make the mind heavy, restless and more sensual - For spiritual progress we need a saumya, shant (calm and gentle) mind, so such foods are avoided.

Digambar and Shwetambar view

• Both traditions (Digambar and Shwetambar) accept the principle that:

- Root vegetables involve more violence. - Foods that excite passions should be avoided by those who want to progress spiritually.

• In practice:

- Strict followers in both traditions do not eat onion, garlic, potato, etc. - Some householders may be less strict, but ideal Jain achar is to avoid them.

So, onion is not allowed mainly because:

• It causes more himsa to many jiv when uprooted, and
• It is considered asātvik / disturbing for a peaceful, spiritual life.