A mother has been arrested in the US after her seven-year-old son turned up to school high on cocaine, it has been reported.

Teachers called paramedics after the youngster became drowsy and unresponsive at North Elementary School in Urbana, Ohio.

Hospital doctors discovered the class A drug in the boy’s system after running tests, according to local news channel WDTN.

His mother, who has not been named, was detained by police after she arrived at Urbana Mercy Health Hospital to collect the child – and was then herself found to be under the influence of cocaine, methamphetamine and fentanyl.

She told the police the boy may have inhaled the drugs when he was left unattended before school. She is facing multiple charges relating to use and possession of drugs.

Benjamin Cash, a neighbour, told WDTN: “It almost brings a tear to your eye. It's crazy. You got to be thankful for the good staff members and good teachers."