Previous studies on the follow-up effect of serendipity mostly focused on the positive effects and less on the negative effects. Therefore, the purpose of this article is to investigate the negative effect of serendipity on the purchase intention of unexpected products. To verify all hypotheses in this article, we used online and offline survey data in China. Three experimental results showed that serendipity contains a certain degree of uncertainty, which will cause consumers’ perceived risk and decrease the purchase intention of (...) unexpected products. Perceived risk plays a mediating role in the effect of serendipity on the purchase intention of unexpected products. Moreover, regulatory focus moderates the effect of serendipity on purchase intention of unexpected products. Specifically, for prevention-focused individuals, the negative effect of serendipity on the purchase intention of unexpected products is strengthened. For promotion-focused individuals, the negative effect of serendipity on the purchase intention of unexpected products is weakened. This article augments the understanding of the negative effects of serendipity and provides theoretical guidance and support for the management practice of marketers. (shrink)