In Jain Dharma, garlic is avoided because it is considered tamasic and harmful to spiritual discipline. Jain tradition teaches ahimsa and sattva, so food is chosen to minimize harm to living beings and to reduce passions like anger, lust, and attachment.

Garlic is also avoided because it is believed to:

• stimulate the body and mind,
• increase desire and agitation,
• and not support the calmness needed for sadhana and self-control.

So the main reason is to support ahimsa, purity, and spiritual restraint in daily life.