New research on hospital treatment raises concern among parents, as it shows that medicine mix-ups, accidental overdoses, and bad drug reactions harm roughly one of 15 children while being hospitalized.

Researchers, led by Paul Sharek of Stanford University’s Packard Children’s Hospital followed over 900 children’s cases from 12 different U.S. children’s hospitals in 2002.

The study found one in 15 hospitalized children, or more than 540,000 annually, are a subject to a drug mistake or adverse reaction. Nearly 97 percent of the identified adverse drug events resulted in mild, temporary harm mostly involving nausea and pruritis, the study said. However, only 3.7 percent of these events were found in traditional hospital reports.

Other findings of the study included: 22 percent of all adverse drug events were deemed preventable, 17.8 percent could have been identified earlier, and 16.8 percent could have been mitigated more effectively.

The findings highlight the need for “aggressive, evidence-based prevention strategies to decrease the substantial risk for medication-related harm to our pediatric inpatient population,” the researchers said, according to the Associated Press.

“This gives us some valuable insight into the frequency of medication-related harm. The number is larger purely because of the way we collected the information before. But most of those who work in children’s hospitals realize that because of the complexity of children’s health care in the United States harm occurs,” Sharek said.

The study has once again sparked interest in the accidental life-threatening heparin overdoses in a Los Angeles hospital, administered to Dennis Quaid’s newborn twins last November.

Actually, the actor praised the new study and encouraged parents to ask questions and stay in-tune with what their kids are being given in hospital.

“Every time a caregiver comes into the room, I would check and ask the nurse what they’re giving them and why,” Quaid said quoted by the AP.

The study was published Monday in the April issue of the journal Pediatrics.