Bayer shares tumble after court blames Roundup weedkiller for man’s cancer

Shares in Bayer dived more than 10 per cent following a major legal setback for the multinational pharmaceutical giant.

A unanimous decision from a US jury yesterday found that the German-based firm’s Roundup weed killer product was a "substantial factor" in causing a man's cancer.

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Bayer denies allegations that glyphosate or Roundup cause cancer, saying in a statement last night that it was disappointed with the initial decision.

In a statement the firm said: "We are confident the evidence in phase two will show that Monsanto's conduct has been appropriate and the company should not be liable for Mr. Hardeman's cancer."

Bayer, which acquired Roundup producer Monsanto for $63bn last year, saw its shares tumbled just over 10 per cent to €62.4 in early morning trading in Frankfurt.

Some €7bn euros (£6bn) have been wiped off the firm's market value as a result.

Liability and damages will be decided by the same jury in a second trial phase starting today.