Health service users need reliable information to be able to make informed decisions. We evaluated the scientific quality of information presented at a large health fair in Oslo in 1995 and health-related articles in five newspapers during one week in the spring of 1995. The brochures scored consistently low on the index used to measure scientific quality. It was generally impossible to distinguish opinions from facts, or to assess the validity and consistency of the evidence underlying the conveyed information. Important consequences (benefits, risks and costs) were rarely assessed. Health-related articles in the lay press also scored low on the index. Minor changes could have led to marked improvement of some of the articles. It is important to improve the ability of journalists and producers of brochures to appraise their work in a critical light.