Health-related misinformation is widespread online and can adversely affect public well-being. This study examines whether media literacy can effectively combat health misinformation by influencing key stages of the misinformation process: initial credibility discernment, sharing decisions, and response to corrections. We conducted a cross-sectional online survey in China with 693 respondents, assessing their ability to discern misinformation (using both mean rating difference and ROC-based methods), willingness to share information, and continued belief in misinformation after corrections. Results indicated that higher media literacy was associated with better credibility discernment of health information. Media literacy did not significantly associate with sharing discernment; however, respondents with higher media literacy scores exhibited a stronger continued influence effect. Additionally, participants with greater credibility discernment were more discerning in sharing information, although neither discernment index was related to the magnitude of the continued influence effect. These findings highlight a double-edged sword: while media literacy enhances the recognition of false information, it may also engender confidence that makes individuals less receptive to valid corrections. Interventions aiming to combat health misinformation should account for both the beneficial and potentially counterproductive effects of media literacy. The widespread dissemination of health misinformation on the Internet has a detrimental effect on people’s lives.