Stocks fell in volatile trade on Thursday as investors sold off shares of healthcare companies such as Merck & Co on worries that President Obama's budget proposal will strangle profits.

* The Obama plan to expand healthcare coverage and curb costs calls for cutting Medicare payments to private insurers, allowing consumers to buy cheaper medicines and preventing drug companies from making deals that block generic competition.

* The Dow Jones industrial average <.DJI> fell 88.81 points, or 1.22 percent, to 7,182.08. The Standard & Poor's 500 Index <.SPX> lost 12.09 points, or 1.58 percent, to 752.81. The Nasdaq Composite Index <.IXIC> gave up 33.96 points, or 2.38 percent, at 1,391.47.

(Reporting by Leah Schnurr; Editing by James Dalgleish)