One child died and 18 others, including the deputy principal of the Bhekizizwe School in the Eastern Cape were rushed to hospital after an alleged incident of "mass hysteria" on Thursday afternoon, the provincial department of health said.
Spokesperson Sizwe Kupelo said the "hysteria" involved visual and auditory hallucinations.
"When [the] hysteria hit the one girl, she collapsed and died in the classroom. The rest followed [with feeling ill]."
They were admitted to the Ngcwanguba Hospital in the province.
Further details were not immediately available.