A California doctor is fighting for his licence after he prescribed cannabis cookies to a four-year-old boy.
Dr William Eidelman, a natural medicine physician, said small doses of marijuana would help control the child's temper tantrums.
The doctor misdiagnosed the child as having bipolar disorder and attention deficit disorder (ADD).
The Medical Board of California ruled to revoke the doctor's licence but he has launched an appeal.
The board did not seek to revoke the licence because the doctor had prescribed cannabis to a child, which is legal for medicinal purposes in the state of California.
Dr Eidelman was investigated due to being "negligent in his care and treatment" - he had failed to consult a psychiatrist in the case or communicate with the school.
The boy's father consulted Dr Eidelman in September 2012 because his son was misbehaving at school.
The doctor recommended small amounts of the drug, which was revealed when the school nurse was asked to give the boy his cannabis cookies at lunchtime.
As a child, the boy's father had ADHD and bipolar disorder himself and had a negative experience with prescribed medications at the time, saying he felt like a "human guinea pig".
He started using marijuana later in life, saying it helped "calm him" and changed his behaviour towards his wife, towards whom he had previously "exhibited anger".
The father had previously obtained the drug for his older son, who had also been diagnosed with ADHD and bipolar disorder.
He said marijuana had had a "positive effect" on both his children.
Dr Eidelman has appealed against the ruling, made on 4 January, and says he will continue to practise. His lawyers said he had won a suspension of the revocation, pending a future hearing.
Medicinal cannabis usage has been legal in California since 1996, and Dr Eidelman estimates that he has recommended the drug to thousands of patients.