ChatGPT has shown high performance in medical diagnosis, with various enhancement strategies proposed. However, national-level applications remain limited. This study explores integrating a personal medical chatbot into home environments nationwide, using knowledge from the Insieme platform, a robust electronic and mobile health system developed through an Italian-Slovenian project. This integration provides verified medical information, online support from healthcare professionals, and interactions with a virtual assistant powered by advanced natural language processing technologies. Detailed presentations of the Insieme platform and HomeDoctor application introduce innovative solutions for smart city ecosystems, potentially transforming national healthcare by enhancing patient care and optimizing workflows. The approach is based on deploying ChatGPT within the information and knowledge from the Insieme platform, using word embeddings and vector databases for efficient data retrieval and context-aware responses. This integration aims to reduce the burden on healthcare professionals, particularly in areas with workforce shortages, by providing 24/7 accessible and accurate medical information. The national-scale chatbot integration supports multilingual interactions, ensuring accessibility for non-native speakers, using country-specific knowledge. Preliminary studies show high user satisfaction and positive healthcare impacts, demonstrating the potential of integrating advanced AI technologies into national healthcare infrastructures and offering a blueprint for future medical smart-city developments.