The illegal use of gutter oil (GO) as cooking oil is a serious food fraud problem in China and has raised widespread concerns. With the popular use of internet, Koubei, a food ordering app, launched a campaign that every restaurant could pledge on the platform that it is GO free. This paper evaluates whether consumers value the GO-free feature reflected on their willingness-to-pay (WTP) to the claim. Results show the GO-free claim receives a positive WTP, and consumers are even more sensitive to the GO-free pledged by small businesses and independent restaurants. For policy implications, results confirm the advantages that the online platforms have in providing food safety information and alleviating the market failure caused by asymmetric information. It will complement the governments’ efforts in preventing GO use and other fraud behaviors in food markets.