Monsanto Co. has been sued by thousands of farmers and others who blame their cancers on its massively popular Roundup weedkiller. Now Germany’s Bayer AG, which bought the agriculture giant last year, faces a claim that it deceived home gardeners about Roundup’s impact on their gut bacteria and their health.

The lawsuit, filed Wednesday in federal court in Kansas City, Missouri, claims that labels on products such as Roundup’s Weed & Grass Killer falsely assured consumers that they target an enzyme not found “in people or pets.”

According to the suit — which names three consumers as plaintiffs seeking unspecified monetary damages and class action status — Roundup’s active ingredient glyphosate attacks an enzyme also found in the beneficial intestinal bacteria of humans and some animals.

“Monsanto has misled consumers about glyphosate’s risks for decades,” plaintiffs’ attorney Robert F. Kennedy Jr. said in an email. “Despite the company’s efforts to suppress and skew research on glyphosate, the science is in.”