Adverse drug reactions (ADRs) cause a great deal of illness and death, and limit therapeutic options. Some ADRs result from differences in individual genetic make-up, and it is likely that many others have genetic origins. This research seeks to clarify how genes contribute to adverse reactions to drugs used in treatment of common illnesses like hypertension, acid reflux, and depression, within the New Zealand healthcare setting. In parallel with this, we will develop a biobank to collect and store samples from New Zealand patients suffering a much wider range of serious ADRs, to enable ongoing research. Ultimately, knowledge generated in this area will contribute to development of a single test that examines all genes known to be involved in ADRs or that affect responses to drugs, and provision of this test may help prevent ADR and lead to safer and improved treatments for many common illnesses.