A case under section 328 (Causing hurt by means of poison, etc, with intent to commit an offence) and 380 of the IPC (theft) had been registered against two unidentified persons, they said.
The labourers at the purchase centre at village Bhore Sydha, 15 km from here had fallen ill after consuming 'khir', which was offered to them as 'prasad' by the accused yesterday.
The two persons came on a tempo at the purchase centre last night and offered 'khir' (rice cooked in milk), SHO Pehowa, Inspector, Aman Kumar.
Police later reached the spot and the affected labourers to the Lok Nayak Jai Prakash Hospital at Kurukshetra.
Chief Medical Officer, Kurukshetra, Dr K K Sharma, said that the labourers, who hail from Bihar, are being treated at the district hospital for vomiting.
"Their condition is stable, but all have been kept under observation," Dr Sharma said.