According to police, the 21-year-old woman started vomiting when the bus, which started from Delhi this morning, was approaching Ambala, about 200 km from the national capital.
The bus was diverted to Baldev Nagar Police Station here from where the woman was taken in another vehicle under police escort to Civil Hospital here.
She was treated at the hospital and allowed to continue her journey.
The bus left Ambala for Lahore at 10:55 AM.
Police sources said that the woman, who originally hails from Kanpur, is married to a man in Lahore.