Bayer recently closed on the acquisition of Monsanto, and now, it is faced with an emerging crisis around Monsanto’s blockbuster weed killer, Roundup. A judge in San Francisco has allowed lawsuits to go forward that accuse the company of failing to warn that the chemical in Roundup, glyphosate, causes cancer. There are hundreds of suits and damages could run into billions. Monsanto has strenuously denied the substance causes cancer, but now it will have to take its battle to court and hope it can find a sympathetic jury. Chances are not good it can. Chemicals today have a poor image in the minds of Americans. They are no longer the promise of a bright future but substances of pollution and disease. Monsanto will have to fight that perception at the same time it is proving glyphosate is not a cancer-causing agent. This could get expensive for Bayer.