BSF Assistant Commandant Nathuni Ram said the four were arrested from Indo-Bangladesh border near Phulwari in Uttar Dinajpur district of West Bengal.
"We had received intelligence inputs about a group of cough-syrup smugglers trying to cross over to Bangladesh. Accordingly, we formed a team and laid a trap. We recovered several boxes of cough syrup bottles," Ram said.
The arrested persons have been brought to the BSF sector headquarters for interrogation after which they would be handed over to the police, he said.