Despite advances in concept extraction from free text, finding
meaningful health related information from online patient forums
still poses a significant challenge. Here we demonstrate how structured
information can be extracted from posts found in such online health related
forums by forming relationships between a drug/treatment and a
symptom or side effect, including the polarity/sentiment of the patient.
In particular, a rule-based natural language processing (NLP) system
is deployed, where information in sentences is linked together though
anaphora resolution. Our NLP relationship extraction system provides
a strong baseline, achieving an F1 score of over 80% in discovering the
said relationships that are present in the posts we analysed
