Rafiq Sherzai, a doctor of Herat's regional hospital, said Saturday that the students were between 7 and 12 years old and all attended the Fatiha School in the city of Herat, the provincial capital.
Sherzai said all were in good condition. He did not offer a cause for the mass illness.
Abdul Raouf Ahmadi, a spokesman for Herat's provincial police chief, said only a dozen students were affected.
He blamed the children's illnesses on eating "expired beans." He said police were investigating the incident.