What s a few trillion among friends? Add up the Obama administration s plans to save the economy, from the stimulus package to the bank bailouts, and you re talking in excess of $3 trillion to shore up the country s financial system and create more jobs. But even if all that money works its magic and gets the economy growing again, there could be a long-term casualty of issuing so much debt: the U.S. dollar.

Even before the latest bailout plans were unveiled, confidence in the dollar was slipping as America s budget deficits and national debt<now $10.7 trillion<ballooned. Since last summer, the buck has staged a bit of a comeback, rising 21 percent against a basket of major currencies as investors bought Treasurys in a flight to safety. But now that the markets have a handle on the government s stimulus plans, pressure on the buck could resume, says Eugenio Aleman, senior economist with Wells Fargo. Investors tend to dump currencies of countries that issue so much debt. And the dollar could get pounded, he says, if foreign investors lose faith in America s ability to repay the trillions it now owes.

One way to profit off a weakening buck is to buy U.S. companies that get the bulk of their revenue abroad. A weakening dollar helps multinationals like Procter & Gamble (PG, $48), since their foreign earnings are worth more when converted back to dollars. Foreign stocks can also be a good option; their earnings get a boost when their currency gains against the dollar. David Darst, chief investment strategist of global wealth management for Morgan Stanley, recommends a 14 percent allocation to foreign stocks. Companies such as Novartis, British American Tobacco and Nestl generate much of their earnings in foreign currencies, he says, and the dollar s slide would benefit shareholders.

Other pros see bargains in developing economies whose currencies and stock markets have plunged. The Brazilian real, for instance, is down 30 percent against the dollar since last summer. It may not rebound until the global economy stabilizes, but it s helped make Brazilian stocks cheap, says Audrey Kaplan, lead manager of the Federated InterContinental fund. Kaplan likes big exporters like the mining giant Vale (RIO, $14). This is the best opportunity to get into these shares in five years, she says. And if the real drifts down? At least a vacation in Rio will get cheaper.

Still, trying to profit off any currency is never easy, and some experts think the dollar may even strengthen in the near term. It remains the top reserve currency for the world s central banks, which hold more than $2.7 trillion in dollar reserves. And other countries may be in worse economic shape and have to launch their own massive stimulus packages, which could keep their currencies down too, says Aleman. That s why it may be best to avoid betting directly against the buck with an exchange-traded fund based on a single currency. Instead, international funds or foreign stocks are an option. Global firms with rising foreign sales will likely see shares rise when the economy stabilizes, and they could get a tailwind if the dollar resumes its losing ways.

Unilever (UL)
Market value: $56 billion
2008 sales: $59.3 billion
2009 price/earnings: 10
This Anglo-Dutch consumer-goods giant has 12 brands with more than $1 billion in annual sales, including household names like Lipton tea, Dove soap and Hellmann s mayonnaise. Much of its growth is in emerging markets, which could take a hit this year, says Jefferies International analyst Simon Marshall-Lockyer. But the stock trades at a discount to its peers and has a
5.3 percent dividend yield.

Qiagen (QGEN)
Market value: $3 billion
2008 sales: $893 million
2009 price/earnings: 17
Drug companies, labs and academic institutions use this Dutch firm s molecular diagnostic tools, test kits and research instruments. The firm makes the only FDA-approved DNA test for HPV, the leading cause of cervical cancer. Qiagen is also developing new technologies in molecular diagnostics and gene therapy. And sales to customers in academia and government labs have historically been recession-resistant, notes Robert W. Baird analyst Quintin Lai.

Companhia Vale do Rzo Doce (RIO)
Market value: $69 billion
2008 sales: $39.1 billion
2009 price/earnings: 10
The commodities bust has taken its toll on this Brazilian mining giant, the world s largest producer of iron ore. Shares are down 59 percent over the past year, and analysts expect 2009 earnings to fall 26 percent, to $10.8 billion. But the company has cut back production at its highest-cost mines, and the stock should rebound when the global economy recovers, says Audrey Kaplan, lead manager of the Federated InterContinental fund.