HOPEWELL, Va. (WRIC) – Seven children were rushed to the hospital Wednesday after taking what officials believe to be a prescription medication at a Virginia home.

Hopewell police said that three of the children — aged 1, 2 and 3 years old — are in serious condition. The other four children are expected to be OK.

Police said the woman watching the children called Hopewell Fire and EMS when she realized the kids “weren’t acting right.”

According to police, the fire department arrived and immediately found four children — a 1-year-old, 2-year-old, 3-year-old and 4-year-old — lethargic and unresponsive but breathing. The other three children were later found in the house. All were taken to the hospital.

The fire department contacted Hopewell police believing that an overdose or poisoning had occurred.

Officials said some of the children had been dropped off at the house by their mother, who was leaving them in the care of a woman who had other children in the home. Sometime during the day, the woman babysitting left the kids to go to the store, police said.

The woman allegedly told police that she let someone else in the house know that she was leaving, but said he may not have understood to watch the children while she was away. Police have not clarified whether the children were home alone.

The woman noticed the children were acting strangely when she got back to the house, although she didn’t immediately think anything of it, police said. She then saw an empty prescription bottle on the floor and realized the children may have ingested the medication, according to police.

Police haven’t determined where the bottle came from or how the children got their hands on it. According to officials, the prescription was not immediately identifiable, as it was an old bottle and the label had been rubbed off.

Authorities contacted Child Protective Services after the incident. The Commonwealth Attorney’s Office was also contacted.