$1.4 billion, topping an earlier bid by Bayer AG.
The British consumer goods company said the deal will build on its health care business in the U.S., where it already sells brands such as Muxinex, Delsym and Durex. Schiff products include Tiger's Milk nutrition bars and Airborne immune system health supplements.
Reckitt first made the $42 per-share offer earlier this month only weeks after Bayer offered $34 dollars per share for the Salt Lake City-based company. The German drugmaker later said it did not want to engage in a bidding war for the company.
Schiff's board has approved the deal and urges stockholders to tender their shares. The offer expires Dec. 14.
Shares of Schiff increased 4 cents to close at $41.90. Its shares are up nearly 81 percent since late October, before the bidding for the company began.