Medicine messages are disclosed to the public in the form of written information through legal
procedures. They are delivered to recipients through various channels. The recipients perceive the
efficacy and side effects of medication through these messages and communication channels. This
perception can affect their medication behavior. Therefore, understanding how messages related to
side effects in written medicine information are perceived by recipients may be a starting point for
solving global public health problems, specifically the problem of medication non-adherence. Based
on these problems, this study analyzed how current written medicine information is perceived by
recipients. In current study side-effect message factors were divided into structure and expression of
the message. The message structure was designed with attention-distributed and integration types,
and the message expression was designed with numerical and verbal expressions. The intention
toward medication nonadherence and the message effect path were analyzed according to the
message factors. The results indicated that the side-effect message structure affected medication
non-adherence mediated the cognitive load. Furthermore, the expression of the side-effect message
affected medication non-adherence, which mediated the perceived likelihood of side effects.
Specifically, when body organ information was included in the side-effect message, the intention
toward medication nonadherence increased along with the increase in the cognitive load, and when
the perceived likelihood of side effects was verbally expressed, the intention toward medication
non-adherence was overestimated. Theoretically, this study expanded the cognitive load theory and
anchoring effect to include side-effect messages. Specifically, the mechanism of perception of
distorted side effects was explained by cognitive load and the anchoring effect. These attempts are
meaningful in that they analyzed medication non-adherence, which is a problem in the practical field,
as a communication process between written medicine information and the recipient. They verified
the theoretical validity of the message effect. In practice, this study empirically verified the
improvement draft in the foreign written medicine information section and proposed the direction of
medicine messages to policy makers of health institutions. It also verified the relationship between
medicine messages and medication behavior to provide meaningful insights to field medical and
pharmaceutical experts. This study demonstrated that side effect message structure and expression on
the written medicine information can impair message recipient health outcomes. Currently, in Korea,
despite the difference in the ability of the general public and experts to understand health
information, they are exposed to the written medicine information in the same form. However, the
United States, Europe, and Australia distinguish between medicine information written for medical
professionals and that written for patients. Therefore this study suggested the need for the
improvement of written medicine information centered on the message recipient.