The Dow Jones index of the top US 30 businesses fell 275.67 points to close at 9269.50, wiping out much of last week's gains when optimism largely ruled.
McDonald's said its profits next year will miss Wall Street's expectations and that the global economic slowdown will force it to cut back new store openings. It will pay $200m (€221.05m) in the next quarter to cover redundancy costs.
The dollar lost almost two cents against the pound, closing at $1.4515, and shed 0.7 cents against the euro, closing in London at 89.73 cents.
Dealers said the dollar's weakness was due to growing fears that a raft of data this week, culminating in unemployment figures on Friday, will reveal that the US economy has fallen into recession since Terror Tuesday.