Ten students were hospitalised on Thursday following a hepatitis A outbreak at Moi High School Mbiruri in Embu County.
The boys were rushed to Tenri private hospital after complaining of stomach pain and general body weakness.
Hepatitis A results from consuming food or water contaminated with the hepatitis A virus or from close contact with an infected person or object.
According to the World Health Organization, "Almost everyone recovers fully from hepatitis A with a lifelong immunity".
The WHO says the disease is rarely fatal but that "a very small proportion of people infected with hepatitis A could die from fulminant hepatitis (acute liver failure)".
A vaccine prevents infection.
The boys were diagnosed with hepatitis A, Tenri Medical Superintendent, Dr George Kimani, confirmed.
When the Nation visited the hospital, nurses were busy attending to students who had been put on drips.
As news of the outbreak spread, shocked parents flocked to Tenri for reports on their children.
"I was at home in Manyatta when I was informed that my grandson had been admitted. I immediately travelled to the hospital to see him. I'm happy he is talking," said Mr James Kinuthia.
Dr Kimani said the students were stable and responding well to treatment.
"The disease is being managed. It will clear without complications. The boys are out of danger ... there is no cause for alarm," he said.
County Health Chief officer, Grace Muriithi, said she held a meeting with Health executive Dr Joan Mwende and established that the situation was under control.
"We are taking the matter seriously. Public health officials were dispatched to the institution," she said.
Embu's Director of Education James Kariuki said education officers were sent to the school for an assessment.
County Assembly Health committee chair Muturi Mwombo told the school administration to ensure cleanliness to prevent such cases.
"Children are supposed to live in hygienic environments so they [do not contract] contagious diseases," he said.