A crying toddler has desperately tried to wake her unconscious mother in a US supermarket after she collapsed from a suspected drug overdone.

Dressed in her pink pyjamas, the two-year-old girl frantically grabbed her mother's hand and pulled her head in an attempt to wake her.

Paramedics arrived shortly after 10.30am on September 18 and administered Narcan to the 36-year-old New Hampshire woman, a medication used to reverse the effects of opiate and heroin overdoses.

Police reportedly found drug paraphernalia in the mother's bag before she was transported to hospital for treatment.

Lawrence police captain Roy Vasque said the incident highlighted one of the worst aspects of drug addiction, the Eagle Tribune reports

"To put a child in such a situation shows how strong the addiction is," he said.

"It's definitely common for children to act in this way, and we have seen this before."

Store clerk Nicaurys Anziani said the mother collapsed shortly after arriving at the store.

The girl "was just crying and crying and crying," she said.

The 36-year-old denied she had overdosed and told paramedics "she was just tired and dozed off," a witness said.

Laurence police Chief James Fitzpatrick said while video footage of the incident may be confronting for some, it helped highlight the dark realities of habitual drug use.

"It’s very disturbing to see someone like this. It’s obvious addiction has overtaken them, to the point of not being able to care for their child," he told WBZ-TV .

The toddler is now in government custody while her mother awaits a court appearance.

Earlier this month US police took a photo of 50-year-old Rhonda Pasek, and her friend James Lee Acord passed out from a reported drug overdose in a 4WD while her grandson sat in the back seat.