That pulled down prices for oil, gold and other Canadian commodities. Prices were also weighed down by a stronger greenback, which was seen pressuring demand for dollar-priced commodities. Gold fell more than 2 percent to hit a two-week low, while oil slipped below $78 a barrel.
"We've seen another surge in the US dollar and that's really impacted commodity prices," said Elvis Picardo, analyst and strategist at Global Securities in Vancouver. The top two drags on the index were Barrick Gold, down 2.96 percent at C$39.70, followed by Goldcorp, down 3.8 percent at C$40.02.
Suncor Energy dropped 0.87 percent to C$36.61. The Toronto Stock Exchange's S&P/TSX composite index ended down 84.10 points, or 0.71 percent, at 11,679.32. Seven of its 10 main groups were lower.
Earlier, the index fell as low as 11,581.64, partly on disappointment with IBM's 2010 outlook, released late on Tuesday, which investors viewed as pointing to a slowdown in profit growth. The S&P/TSX composite, which has rallied since March on economic recovery hopes, is now taking direction from waves of earnings reports and corporate financial forecasts, mostly from the United States so far.