An abundance of information is available on the Internet. At the same time the quality of information fluctuates largely. When people use such information for making important decisions, this becomes an issue. “Health” is one of the most searched topics on the Web and search results might have the biggest consequences for one’s life. However, trust in found information, or lack thereof, filters usage. To understand which elements on a website convince people to trust the information or not, we conducted a study with two aims: firstly, identify factors which trigger credibility; secondly, investigate to what extend both the medial presentation and the severity of the related disease influence the assessment of credibility. Possible factors were first collected in three focus groups and then operationalized in a questionnaire. We collected 184 responses where three different health websites differing in complexity and in the severity of disease (light vs. life striking) were presented and assessed. Results show that for more severe diseases more complex information is preferred. Further actually being ill influences the criteria significantly.