A history of research on radio frequency radiation, and recent scant research on the newly emerging 5G suggests that the expansion of 5G poses a possible public health issue. The media play a decisive role in how the public responds to a public health issue, and what it knows about it. However, there is an increasing amount of misinformation on health topics in the media. The present case study investigated whether the Croatian news website Index.hr manipulates information on the health effects of 5G. We constructed one experimental corpus, containing all articles by Index.hr on health effects of 5G, and two control corpora, one with articles about health effects of 5G published by reliable mainstream media, and one with articles about science (but not 5G) published by Index.hr. We assessed the presence of references, scientific references, misinformation, opinion expression, and opinion subjectivity. Compared to Index.hr science articles, Index.hr 5G articles were 10.78 times likelier to contain no references, 4.20 times likelier to contain no scientific references, 10.78 times likelier to contain misinformation, 288.14 times likelier to express the author’s opinion on the issue, and 16.95 times likelier to express a subjective opinion. The simultaneous increase in misinformation and reduction in referencing suggests that misinformation doesn’t stem from other unreliable sources of information, but that the misinformation is produced within Index.hr. An increase in opinion expression, and opinion subjectivity in the context of misinformation suggests that Index.hr is manipulating the information on health effects of 5G. This is corroborated by the fact that the two types of misinformation identified in the present study included erroneous referencing, and denial of the existence of scientific literature on the topic. Furthermore, all articles on both 5G, and scientific topics were written by different authors, indicating that this phenomenon is systematic within Index.hr. We conclude that our data point to a manipulation of information on health effects of 5G by Index.hr. Still, the small sample size warrants a degree of caution.