In graphic design, colours can be used to communicate a message and attract attention. In book design, colours convey the content, just like they communicate the product’s information in packaging design. The purpose of this study is to analyse how colours have been used on book covers to convey the content, within the topic of health. A quantitative content analysis was made on the book covers of the top 11 bestsellers in Sweden. The colour theory analysis is based on Shigenobu Kobayashi’s work in Colour image scale. The result found that neutral hue was the one that was most commonly used. Additionally, the analysis revealed some correlation between the book content and the colour combination on the book covers. For example, a book related to finding happiness had a colour combination that matches a casual and natural lifestyle. Although the analysis offered some insight within the subject of colour and book design, further studies are needed in order to understand the extent of how colours are being used towards communicating the content.