Many U.S. fund managers these days seem to be taking a recommendation attributed to Nathan Mayer Rothschild, the 18th century financier, to heart amid the European debt crisis: Buy when there's blood in the streets.

The Wall Street saying refers to the belief that buying cheap assets when others have sold them in fear often yields great profit.

The Greek debt crisis has weighed on European stocks, making some potential bargains.

Some fear that euro zone sovereign bonds defaults will wreak havoc on the European financial system  Others fear an eventual breakup of the euro zone and its single currency.

Eventually, a Greek politician will say, 'Vote for me, and I'll get us out of this system,' warns Hugh Hendry, a contrarian hedge fund manager, in a recent Barron's interview.

European stocks have been hammered by such persistent fears. The euro, too, has fallen against the U.S. dollar, which means European stocks have doubly depreciated against U.S. stocks.

The SPDR STOXX Europe 50 ETF, an exchange-traded fund that represents the performance of 50 large European companies, is currently trading at a dividend yield of 4.44 percent. The Euro STOXX 50 Index includes Total SA, Sanofi, Banco Santander and Allianz. It has a forward one-year price-to-earnings ratio of 10.04 and a price-to-book ratio of 1.60, according to State Street Global Advisors.

Meanwhile, the SPDR S&P 500 ETF, a portfolio representing all 500 stocks in the S&P 500 Index, is trading at a dividend yield of 2.09 percent. It has a forward one-year price-to-earnings ratio of 12.88 and a price-to-book ratio of 2.02.

Mason Hawkins, a value investor at LongLeaf Partners Funds in Memphis, sees value in distressed European stocks. The firm's international fund has 40 percent of its assets allocated to France, Ireland and Spain, according to ValueWalk, a financial news website.

Spain's Ferrovial SA, which develops transportation infrastructure like airports and toll roads, makes up 6.4 percent of LongLeaf's international fund.

Warren Buffett, the legendary Omaha-based investor, is also bullish on Europe.

In a CNBC interview a week ago, Buffett said he put €175 million ($232.2 million) into each of eight European stocks on behalf of Berkshire Hathaway at the end of 2011. The names of the stocks weren't immediately known.

I just thought these eight companies were cheap, said Buffett.

Though he acknowledged the challenges posed by the European debt crisis, Buffett said he's confident the companies he bought have staying power and and will do fine regardless of what happens in Europe.

There's always going to be something that's bothering the world, he noted.