Shire specializes in developing, producing, and marketing pharmaceutical products for the treatment of nervous system dysfunctions (hyperactivity, epilepsy, Alzheimer's disease, etc.), cancer, gastro-intestinal illnesses, and infectious diseases. Net sales break down by source of income as follows:
- sales of products (95.3%);
- other (4.7%): primarily franchise royalties.
Net sales break down geographically as follows: the United States (63.6%), Ireland (0.4%) and other (36%).