The stock market had its worst drop this year as prices for oil and other commodities fell sharply on concerns about slowing growth in China.
Oil fell to a four-month low, dragging down energy stocks. Mining companies sank after gold had its biggest one-day drop since 1983.
The Dow Jones industrial average fell 265.86, or 1.8 percent, to close at 14,599.20.
The S&P 500 index fell 36.49 points, or 2.3 percent, to 1,552.36.
The Nasdaq composite fell 78.46 points, or 2.4 percent, to 3,216.49.
For the year:
The Dow is up 1,495.06 points, or 11.4 percent.
The S&P 500 is up 126.17 points, or 8.9 percent.
The Nasdaq is up 196.98 points, or 6.5 percent.