The paper discusses an eHealth project which is currently developing an interactive web-based platform that assists patients to self-manage work-related disorders and alcoholism. The focus is on motivating long-term behaviour change. This is supported by an online assessment component based on the technique of motivational interviewing and a feedback component which visualizes actual behaviour in relation to intended behaviour. Disease-specific information is provided through an information portal that utilizes lightweight ontologies (associative networks) in combination with text mining. Emotional support is provided via virtual communities. The paper discusses the design rationales underlying the approach taken and outlines some implementational aspects. The paper also briefly outlines how the effectiveness of the self-management tool will be measured based on an outcome model particularly suited for health promotion.