When Christopher Herrera, 17, walked into the emergency room at Texas Children’s Hospital one morning last year, his chest, face and eyes were bright yellow — “almost highlighter yellow,” recalled Dr. Shreena S. Patel, the pediatric resident who treated him.

Christopher, a high school student from Katy, Tex., suffered severe liver damage after using a concentrated green tea extract he bought at a nutrition store as a “fat burning” supplement. The damage was so extensive that he was put on the waiting list for a liver transplant.

“It was terrifying,” he said in an interview. “They kept telling me they had the best surgeons, and they were trying to comfort me. But they were saying that I needed a new liver and that my body could reject it.”

New data suggests that his is not an isolated case. Dietary supplements account for nearly 20 percent of drug-related liver injuries that turn up in hospitals, up from 7 percent a decade ago, according to an analysis by a national network of liver specialists. The research included only the most severe cases of liver damage referred to a representative group of hospitals around the country, and the investigators said they were undercounting the actual number of cases.