The lawsuit was filed by Regina Jackson, a 55 year-old woman who spent a week in the hospital after accidentally overdosing on Tylenol in February 2011.
After a four-week trial, the jury in New Jersey decided not to rule on the safety of Tylenol because they were not sure whether Jackson took Extra Strength Tylenol or the regular version.
Extra Strength Tylenol contains 500-mg of acetaminophen, versus 325-mg in regular-strength.
The verdict comes as J&J faces about 220 Tylenol lawsuits in state and federal court. The first federal trial is scheduled for early next year in Philadelphia, where about 200 cases are consolidated.
Lawsuits accuse drug-makers of downplaying the narrow margin of safety for acetaminophen. Tylenol breaks down into a powerful toxin and the body can only metabolize a limited amount. Taking just a little too much can cause liver damage.
In 2006, the American Liver Foundation warned that taking the maximum daily dose of Tylenol for two weeks could elevate liver enzymes and lead to liver damage.
After the FDA warned against taking even a tiny amount over 4,000-mg of acetaminophen per day, J&J voluntarily lowered the maximum recommended dose to 3,000-mg per day in July 2011. Most lawsuits involve accidental overdoses of Tylenol before the change.