The collateral damage of the euro on the US

Cramerica can credit Thursday's rally to the president of the European Central Bank, Mario Draghi. However, as the averages roared on, Jim Cramer became increasingly concerned that throwing in billions of euros to stimulate Europe's economy could cause problems for investors' portfolios.

It's the weakening euro that worries Cramer, and he thinks that the ECB-style quantitative easing could kill a lot of companies in the U.S.

Will it work? Who knows?

"The fact is that six years after our central bank decided that it is not acceptable to have high unemployment, the Europeans are finally getting the message. And not a moment too soon," said the "Mad Money" host.

Scott Eells | Bloomberg | Getty Images

American Express cards are arranged for a photograph in New York.

Cramer saw that because of the lockstep nature of how stocks trade, a lot of stocks that should not have rallied on Thursday. As he listened to conference calls for companies reporting earnings this week, all he is hearing about is the moaning and groaning of CEOs complaining about getting crushed because it has become so hard to do business overseas.

Currency headwinds, they call it. After all, everyone wants to visit Europe. They just don't want to do business there.

"You don't need a weatherman to know the wind is blowing against these U.S. companies with lots of overseas exposure, especially in Europe," Cramer added.

And the "Mad Money" host is seeing the weakness of the euro creep into the profitability of many U.S. based international companies, including American Express, Johnson & Johnson and IBM.

Meanwhile, the domestically focused businesses are happier than ever. Companies like Northern Trust and KeyCorp are relieved that they have nothing to do with Europe. And how excited is Union Pacific that it doesn't build a railroad over the ocean?

Another cohort that is immune to European headwinds is biotech. Neither TG Therapeutics nor Amicus is bound by currency issues, and they could present an opportunity.

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Read more from Mad Money with Jim Cramer:
Cramer Remix: Hold this stock for the long term
Cramer: A life-saving biotech with a personal mission
The ripple of 'cult stocks' in the market rally
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At the end of the day, Cramer wants all investors to take a pulse of their portfolio exposure. Are you too internationally oriented?

"Tomorrow, Mario Draghi's not going to do something dramatic again, and we'll be stuck with the tsunami of overseas and the tranquility of domestic earnings abetted by lower oil, and believe me, there's plenty to choose from."

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