Denise Manzella, 28, of Staten Island, told police she left two of her prescribed oxycodone pills on top of a microwave last week as she was preparing snacks for her daughters, ages 3 and 5.
While Manzella was distracted, the 3-year-old allegedly slipped the pills into a jelly sandwich and urged her mother to eat it, The Staten Island (N.Y.) Advance reported Tuesday.
The sandwich instead ended up on a plate with other cut-up sandwiches, which Manzella's daughters shared with neighbor girls whose grandmother checked the sandwiches, found the pills and alerted police.
Manzella was charged with two counts of endangering the welfare of a minor.
"It was a simple accident," Manzella told the Advance. "It was my fault. It wasn't carelessness on my part. It was an accident on my part."
Jordana Brewster on Paul Walker: 'He was an enormous presence in my life'
Exploding whale video goes viral on Internet