Systemic-Functional Linguistics often appears as a complete and altogether exhaustive theory of language. If widened with a multimodal perspective, social semiotics seems to contain all you need – but does it? The research project Health literacy and knowledge-formation in the information society has investigated complex communication practices related to the pre-natal diagnosis of heart failure in children, pursuing linguistic purposes as well as educational and applied goals. Oral consultations, digital discussions, written texts and visual representations were studied across different contexts and epistemic cultures, from the medical consultation room to the private blog, using tools from SFL and social semiotics (e.g. genre analysis, systemic conversation analysis and Legitimation Code Theory) – but also tools from other traditions and disciplines (e.g. New Literacy Studies, Activity Theory and rhetoric). Based on examples from these studies, this paper discusses the strengths and limitations of SFL and social semiotics, both with respect to their potential to provide adequate analytical tools for complex and context-overarching meaning-making practices, and with respect to their compatibility with other relevant perspectives and disciplinary traditions, e.g. those of medical professionals.