So, one day, Duryodhana poisoned the food that Bhima ate. Duryodhana and his brothers then tied Bhima up with wild vines and critters and threw him into a part of the Ganges where they had earlier placed sharp spikes. Fortunately for Bhima, he did not get impaled by the spikes. Even more fortuitously, poisonous snakes lived in the water where his cousins threw him.
He was bit by the water-snakes. The poison of these snakes counteracted the poison he had eaten and Bhima became conscious again. He broke out of the vines with which he had been tied, got out of the water and made his way back to Hastinapura.
Such was the luck of the sons of Pandu that the counteracting poisons made Bhima stronger than ever before.