DENVER -- In a recovery room at Porter Adventist Hospital, Melissa Willie says she's fortunate to be spending time with three of her young children after suffering liver failure and a coma. It all started with pain in her abdomen.

"I took Tylenol and it wouldn't go away," Willie said. "So I kept taking more and more."

She was unaware that taking too much acetaminophen, which is the active ingredient in drugs like Tylenol and Excedrin, could damage her liver.

"You shouldn't really take more than 2 grams a day for a long period of time, but she probably took about 50 grams," said Dr. Tom Heffron, of Porter Adventist Hospital.

Willie took the equivalent of 100 500 milligram pills over the course of about four days.

"The consequences are that you could go into liver failure and die from that," Heffron said.

He added that patients in acute liver failure, like Willie, typically survive only one to two days, which is why he performed a rare procedure, transplanting a liver from a donor with a different blood type.

"By utilizing all blood groups we were able to give Melissa an option for any liver that was available," Heffron said. "If we wouldn't have crossed blood groups, she wouldn't have obtained this liver and probably wouldn't have gotten a liver in time to live."

Nearly one month after the surgery, Willie is still recovering at the hospital. She says being away from her kids has been difficult, but she's just grateful she'll have the chance to be there for them as they grow up.

As of April 2010, the FDA started requiring manufacturers to update warning labels about the risk of severe liver damage from too much acetaminophen, and to prominently display the active ingredients on the box and bottle.