Suits for "false patent marking" have been the rage. Under the patent laws, it is permissible to mark your products and packaging with your current patent number(s) and include them in your advertising. Also under the patent laws, however, it can be illegal to mark products or packaging with patent numbers after those patents have expired or use expired patent numbers in advertising. Not only the government, but "any person" can file qui tam lawsuits seeking penalties for false patent marking - up to $500 for every offense. Hundreds of qui tam lawsuits were filed in 2010 for false patent marking. The reason for this deluge is a decision by the Federal Circuit Court of Appeals in late 2009, Forest Group v. Bon Tool Co., that proclaimed that the statutory penalty applies not to each product line, but rather to each item falsely marked. Some cases are holding that even if a product contains multiple patent numbers, some of which have not expired, it can still be a violation if any of those patent numbers has expired. Since the person bringing a qui tam lawsuit is entitled to keep 50% of any penalty (the other 50% going to the government), it is no wonder so many suits are being filed. While the false marking qui tam statute has been declared unconstitutional by one Ohio Federal District Court recently, the stakes are high, so check your products, packaging and advertising, and immediately remove any expired patent numbers.