CID superintendent of police Niraj Khalij said the seized poison is worth Rs 80 lakh in the country and Rs 1.5 crore in the international market.
The poison was brought from Kalimpong and it is suspected that it was to be smuggled either to Nepal or China for processing into drugs before being sold to other countries.
Khalij said a team of four CID personnel including its special superintendent of police (north) acting on a tip off arrested the four from the hotel adjacent to Siliguri junction railway station.
The arrested were later sent to police custody for four days by the Siliguri fast track court.
