Kṛṣṇa showed the nature of a small baby and closed His eyes, as if to avoid the face of Pūtanā. This closing of the eyes is interpreted and studied in different ways by the devotees. Some say that Kṛṣṇa closed His eyes because He did not like to see the face of Pūtanā, who had killed so many children and who had now come to kill Him. Others say that Pūtanā hesitated to take the baby on her lap because something extraordinary was being dictated to her from within, and in order to give her assurance, Kṛṣṇa closed His eyes so that she would not be frightened. And yet others interpret in this way: Kṛṣṇa appeared in order to kill the demons and give protection to the devotees, as stated in the Bhagavad-gītā: paritrāṇāya sādhūnāṁ vināśāya ca duṣkṛtām (BG 4.8). The first demon to be killed was a woman. According to Vedic rules, the killing of a woman, a brāhmaṇa, cows or a child is strictly forbidden. Kṛṣṇa was obliged to kill the demon Pūtanā, and because the killing of a woman is forbidden according to Vedic śāstra, He could not help but close His eyes. Another interpretation is that Kṛṣṇa closed His eyes because He simply took Pūtanā to be His nurse. Pūtanā came to Kṛṣṇa just to offer her breast for the Lord to suck. Kṛṣṇa is so merciful that even though He knew Pūtanā was there to kill Him, He took her as His nurse or mother.
There are seven kinds of mothers, according to Vedic injunction: the real mother, the wife of a teacher or spiritual master, the wife of a king, the wife of a brāhmaṇa, the cow, the nurse and mother earth. Because Pūtanā came to take Kṛṣṇa on her lap and offer her breast milk to be sucked by Him, she was accepted by Kṛṣṇa as one of His mothers. That is considered to be another reason He closed His eyes: He had to kill a nurse or mother. But His killing of His mother or nurse was no different from His love for His real mother or His foster mother, Yaśodā. We further understand from Vedic information that Pūtanā was also treated as a mother and given the same facility as Yaśodā. As Yaśodā was given liberation from the material world, Pūtanā was also given liberation. When the baby Kṛṣṇa closed His eyes, Pūtanā took Him on her lap. She did not know that she was holding death personified. If a person mistakes a snake for a rope, he dies. Similarly, Pūtanā had killed so many babies before meeting Kṛṣṇa, and she mistook Him to be like them, but now she was accepting the snake that would kill her immediately.
When Pūtanā was taking baby Kṛṣṇa on her lap, both Yaśodā and Rohiṇī were present, but because she was so beautifully dressed and showed motherly affection toward Kṛṣṇa, they did not forbid her. They could not understand that she was a sword within a decorated case. Pūtanā had smeared a very powerful poison on her breasts, and immediately after taking the baby on her lap, she pushed her breastly nipple within His mouth. She was hoping that as soon as He would suck her breast, He would die. But baby Kṛṣṇa very quickly took the nipple in anger. He sucked the milk-poison along with the life air of the demon. In other words, Kṛṣṇa simultaneously sucked the milk from her breast and killed her by sucking out her life. Kṛṣṇa is so merciful that because the demon Pūtanā came to offer her breast milk to Him, He fulfilled her desire and accepted her activity as motherly. But to stop her from further nefarious activities, He immediately killed her. And because the demon was killed by Kṛṣṇa, she got liberation. As Kṛṣṇa pressed her breast extremely hard and sucked out her very breath, Pūtanā fell down on the ground, spread her arms and legs and began to cry, “Oh, child, leave me, leave me!” She was crying loudly and perspiring, and her whole body became wet.