Johnson & Johnson has been ordered to pay $417m (£323.4m) to a woman who says she developed ovarian cancer after using products such as baby powder.
The California jury's decision marks the largest award yet in a string of lawsuits that claim the firm did not adequately warn about cancer risks from talc-based products.
A spokeswoman for Johnson & Johnson defended the products' safety.
The firm plans to appeal, as it has in previous cases.
"We will appeal today's verdict because we are guided by the science," Carol Goodrich, spokesperson for Johnson & Johnson Consumer Inc, said in a statement.
The evidence around any link between talc use and cancer is inconclusive