US stocks have biggest drop since August, led by health care

Hefty losses in health care and technology companies led U.S. stocks sharply lower Tuesday, handing the market its biggest pullback since August and its worst two-day drop since May.

The broad slide, which briefly sent the Dow Jones industrial average down by more than 400 points, erased some of the big gains the market had racked up since the beginning of the year, though the market was still on...