The incident unfolded earlier this month when the girl's teacher noticed she appeared unusually drowsy and refused to eat lunch at school. Her uncle rushed her to hospital, where doctors initially struggled to determine the cause of her symptoms.
Family members later discovered that two guests at the birthday party had brought cannabis gummies and left them behind, the Bangkok Post reported.
The child is believed to have eaten around 10 pieces, leading to a diagnosis of acute cannabis intoxication. She remained unconscious for 24 hours and was discharged on July 4, only to be readmitted hours later due to a high fever and persistent hallucinations.
Her father shared the story online as a public warning and is demanding over 50,000 baht (US$1,533) in medical expenses from the guests involved. Insurance refused to cover the costs due to the involvement of narcotics.
He also voiced concerns about potential long-term effects on his daughter's brain development.
In response, Public Health Minister Somsak Thepsuthin has instructed the Food and Drug Administration (FDA) and provincial health offices to inspect and take legal action against producers or sellers of food, drinks or snacks containing cannabis extracts that exceed legal limits, The Nation reported.
Under Thai law, unauthorized production or sale of cannabis-infused food products carries penalties of up to three years in prison.