In Jain dharma, onions and potatoes (and all root vegetables) are avoided for two main reasons:

1. Ahimsa – non‑violence toward all living beings

- Onion, potato, garlic, carrot, beet, etc. are root vegetables (kand‑mool). - To eat them, the whole plant has to be pulled out from the soil. - When we uproot them: - The entire plant’s life ends. - Countless tiny living beings in the soil and inside the root are harmed. - Jain scriptures class such roots as anantkāy – having countless living beings in one body – so their use causes very large himsā (violence).

1. Effect on the mind (especially onion/garlic)

- Traditional Jain acharyas explain that onion and garlic increase passions (anger, greed, lust, etc.) and disturb mental peace. - For a person walking on the spiritual path, such food is avoided so that the mind remains light and pure.

What is the actual result of eating them?

• Spiritually:

- More pāpa karma (bad karma) is bound compared to eating non‑root vegetables (like lauki, tori, bhindi, peas, etc.), because: - More lives are killed. - There is often strong taste‑attachment (āsakti) to such foods.

• In practice:

- Monks & nuns (both Digambar and Shwetambar) – completely avoid all root vegetables. - Shravaks/shravikas (householders) – are taught that the ideal Jain diet is without onion, potato, garlic and other roots. Many sincere Jain families fully follow this; some are still in the process of improving.

Summary in simple words

If we eat onions and potatoes:

• We cause more violence to tiny lives.
• We collect more bad karma.
• In case of onion/garlic, our mind becomes more disturbed and less suitable for spiritual progress.

Therefore, according to Jain dharma, the best is not to eat onion, potato, garlic and other root vegetables and choose vegetables, grains, dals, fruits that involve less himsā and keep the mind calm.

You can read more on this topic here