Source: Bhima and the snake poison
Duryodhana was very much worried. His father being blind, the kingdom was ruled by Pandu. After his death Yudhishthira, the heir-apparent, would in course of time become king. Duryodhana thought that as his blind father was quite helpless he must, to prevent Yudhishthira’s accession to the throne, contrive a way of killing Bhima.
He made arrangements to carry out his resolve since he thought that the powers of the Pandavas would decline with the death of Bhima.
Duryodhana and his brothers planned to throw Bhima into the Ganges, imprison Arjuna and Yudhishthira, and then seize the kingdom and rule it. So Duryodhana went with his brothers and the Pandavas for a swim in the Ganges.
After the sports they slept in their tents being exhausted. Bhima had exerted himself more than the others and as his food had been poisoned, he felt drowsy and lay down on the bank of the river. Duryodhana bound him with wild creepers and threw him into the river.
The evil Duryodhana had already caused sharp spikes to be planted on the spot. This was done purposely so that Bhima might in falling be impaled on the spikes, and lose his life. Fortunately there was no spike in the place where Bhima fell. Poisonous water-snakes bit his body.
The poisonous food he had taken was counteracted by the snake poison and Bhima came to no harm, and presently, the river washed him to a bank.
Duryodhana thought that Bhima must have died as he had been thrown in the river infested with poisonous snakes and planted with spikes. So he returned to the city with the rest of the party in great joy.
When Yudhishthira inquired about the whereabouts of Bhima, Duryodhana informed him that he had preceded them to the city.
Yudhishthira believed Duryodhana and as soon as he returned home, asked his mother whether Bhima had returned home.
His anxious question brought forth the reply that Bhima had not yet returned, which made Yudhishthira suspect some foul play against his brother. And he went again with his brothers to the forest and searched everywhere. But Bhima could not be found. They went back in great sorrow.
Sometime later Bhima awoke and trudged wearily back home. Kunti and Yudhishthira welcomed him and embraced him in great joy. By the poison that had entered his system Bhima became stronger than before.
Kunti sent for Vidura and told him in secret:
“Duryodhana is wicked and cruel. He seeks to kill Bhima since he wants to rule the kingdom. I am worried.”
Vidura replied: “What you say is true, but keep your thoughts to yourself. For if the wicked Duryodhana is accused or blamed, his anger and hatred will only increase. Your sons are blessed with long life. You need have no fear on that account.”
Yudhishthira also warned Bhima and said: “Be silent over the matter. Hereafter, we have to be careful and help one another and protect ourselves.”
Duryodhana was surprised to see Bhima come back alive. His jealousy and hatred increased. He heaved a deep sigh and pined away in sorrow.