Bayer said that it would appeal the verdict.
"The verdict in this trial has no impact on future cases and trials, as each one has its own factual and legal circumstances," the company said.
The company noted that none of the California verdicts have been considered by an appeals court and that the US Environmental Protection Agency considers the weed killer safe.
The EPA reaffirmed its position in April, saying that the active ingredient glyphosate found in the weed killer it posed "no risks of concern" for people exposed to it by any means — on farms, in yards and along roadsides, or as residue left on food crops.
Lawsuits have battered Bayer's stock since it purchased Monsanto for US$63b last year and Bayer's top managers are facing shareholders discontent.
- AP