There are no cheap ways to defend international patents. But once you've staked a claim in a country, it can pay to sue for smallinfringements every so often; a small suit can serve as a deterrent to other potential violators. "If you don't take an aggressivestand, the patent, in some cases, can be deemed ineffective," says Ross Mitchell, president of Acclimator Time, in Newton,Mass., which manufactures a jet-lag watch.

But lawsuits are lengthy, expensive, and stressful. Litigation should be far down on your list of intellectual-property priorities.One first step is to write a nonthreatening but firm letter to violators emphasizing your sole right to sell your invention or servicein that country or bloc. Mitchell, for instance, has even asked violators if they want to become licensees. If the firstletter is ignored, write a cease-and-desist order, with the help of a lawyer native to the perpetrator's country. Your generalliability insurance may help cover legal fees.