Mentha oil futures for January fell by Rs 7, or 0.51%, to Rs 1,345.10 per kg in 486 lots.
At the Multi Commodity Exchange, the February contract declined by Rs 6.90, or 0.50%, to Rs 1,359 per kg in 127 lots.
Profit-booking by speculators at prevailing higher levels, weak spot market demand affected the trade.
Adequate stocks in physical market following increased arrivals from Chandausi also fuelled the downtrend.
Investors reducing their positions due to weak demand from pharmaceutical industries weighed on mentha futures trade.