Bayer said in a statement the decision to reduce the damages was a step in the right direction, but it would still file an appeal with the California Court of Appeal, because the verdict was not supported by the evidence presented at the trial.
"According to an earlier hearing, the judge toyed with the idea of dropping the damages altogether," brokerage alpha said in a note to clients. "Now, however, the judge made a U-turn and confirmed the jury's previous verdict."
Monsanto, which denies the allegations, had asked the judge to throw out the entire original $289 million verdict or order a new trial on the punitive damages portion.
A jury on Aug. 10 found the company's glyphosate-based weed-killers, including RoundUp and Ranger Pro, had caused Johnson's cancer and that the company failed to warn consumers about the risks.
The verdict wiped 10 percent off the value of the company and marked the first such decision against Monsanto, which faces more than 8,000 similar lawsuits in the United States.
The German company, which bought Monsanto this year for $63 billion, says decades of scientific studies and real-world use have shown glyphosate to be safe for human use.
Lawyers for Johnson in a statement on Monday said they were still reviewing whether to accept the reduced award or retry the punitive damages portion.
"The evidence presented to this jury was, quite frankly, overwhelming," the lawyers said.
The amount of punitive damages is limited by law, and Bolanos said California's constitution did not permit a higher award. If Johnson accepts the reduced damages, the final verdict would order Monsanto to pay a total of $78 million, split equally between compensatory and punitive damages.
Bolanos' Monday decision is a turnaround from a previous tentative ruling she issued on Oct. 10.