Lorem ipsum是指一篇常用于排版设计领域的拉丁文文章，主要的目的为测试文章或文本在不同字体、版型下看起来的效果。中文的类似用法则称为乱数假文、随机假文。

Lorem ipsum从15世纪开始就被广泛地使用在西方的印刷、设计领域中，在电脑排版盛行之后，这段被传统印刷产业使用几百年的无意义文本又再度流行。由于这段文本以「Lorem ipsum」起头，并且常被用于标题的测试中，所以一般称为Lorem ipsum，简称为Lipsum。

常见的Lorem ipsum起头如下：

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

In publishing and graphic design, lorem ipsum (derived from Latin dolorem ipsum, translated as "pain itself") is a filler text commonly used to demonstrate the graphic elements of a document or visual presentation. Replacing meaningful content with placeholder text allows viewers to focus on graphic aspects such as font, typography, and page layout without being distracted by the content. It also reduces the need for the designer to come up with meaningful text, as they can instead use quickly-generated lorem ipsum.