Last Modified on October 30, 2026
Accidentally infringing on a patent? It happens, but even if it’s unintentional, you can still face legal trouble. No, you won’t go to jail for it—it’s not criminal—but the patent holder can still take legal action. Most of the time, they’ll start by sending a cease and desist letter.
If you haven’t sold anything yet, they’ll probably just ask you to stop. Change the product, pull it from the market, and that’s often the end of it. No major lawsuits, no big damages. But if you’ve already invested a lot or have backers putting money into your product, that’s a different story. You might need to pay for a license to keep selling it or even buy the patent rights.
What throws people off is that you don’t need to know you’re infringing to be liable. In most legal situations, you have to know you’re doing something wrong. Not here. If a patent or trademark is filed with the U.S. Patent and Trademark Office, you’re expected to know it exists. That’s why people get frustrated when they’re hit with a cease and desist. They didn’t know. But in this case, not knowing isn’t an excuse.
What to Do If You Get a Cease and Desist Letter
Do not ignore it. Your first step should be to talk to an experienced patent attorney. The attorney will review the patent claims, work out whether they actually apply to your product, and tell you whether there is a real case for infringement. If you keep selling after you have been told about the patent, the patent holder can pursue triple damages if they prove the infringement was willful.
Your Options
Settle or take a license. A license lets you keep selling in exchange for a flat fee or ongoing royalty payments. That can make sense if you have already paid for manufacturing, marketing or distribution. Patent holders who do not sell products themselves, often called non-practicing entities, usually want money rather than exclusivity and may be open to a license.
When a license is not on the table. If the patent holder sells a competing product, they may refuse to license, especially if your product costs them market share. They can ask a court for an injunction that stops your sales, and you may have to change the product or leave the market.
Weigh the cost of a fight. If your product has only been on the market a short time, damages may be small and settling can be the sensible choice. If it is well established, the risk is higher. Larger companies with big patent portfolios are more likely to sue, and litigation is costly and slow, which hurts small businesses most. A patent attorney can tell you what each path is likely to cost.
Search before you launch. Thorough patent searches before a product goes to market are the best way to avoid accidental infringement in the first place.
