A pupil at St Mary's Primary School in Mugumo location, Kinangop constituency in Nyandarua, has died.
The pupil had complained of headache, chest and stomach pains.
23 other pupils have been admitted at Engineer Hospital with similar symptoms.
Confirming the incident, Nyandarua County Director of Health Dr Jane Mwathi said a team of officials had been dispatched to carry out investigations.
"It is true that we have lost one pupil. The others have been admitted for further examination," said Dr Mwathi.
