  Smart healthcare has achieved significant progress in recent years. Emerging
artificial intelligence (AI) technologies enable various smart applications
across various healthcare scenarios. As an essential technology powered by AI,
natural language processing (NLP) plays a key role in smart healthcare due to
its capability of analysing and understanding human language. In this work, we
review existing studies that concern NLP for smart healthcare from the
perspectives of technique and application. We first elaborate on different NLP
approaches and the NLP pipeline for smart healthcare from the technical point
of view. Then, in the context of smart healthcare applications employing NLP
techniques, we introduce representative smart healthcare scenarios, including
clinical practice, hospital management, personal care, public health, and drug
development. We further discuss two specific medical issues, i.e., the
coronavirus disease 2019 (COVID-19) pandemic and mental health, in which
NLP-driven smart healthcare plays an important role. Finally, we discuss the
limitations of current works and identify the directions for future works.
