The 30-share barometer, which had gained 274.05 points in the previous three sessions, lost 65.76 points, or 0.31 per cent, to 21,271.91 in first five minutes of trade.
Stocks of oil and gas, banking, FMCG and realty sectors led the fall.
Similarly, the National Stock Exchange index Nifty shed 3.95 points, or 0.06 per cent, to 6,335.00.
Brokers said emergence of profit booking by funds as well as retail investors amid a mixed trend in the Asian region influenced the trading sentiment here.
The US Dow Jones Industrial Average ended 0.25 per cent lower in yesterday's trade.