The histamine H(3) receptor is involved in the central and peripheral regulation of levels of histamine and other neurotransmitters (e.g., acetylcholine, noradrenaline, dopamine, serotonin and GABA), which sets it up as a target in the treatment of various CNS (e.g., depression, schizophrenia, ADHD, dementia, neuropathic pain and sleep disorders), metabolic syndrome (e.g., obesity) and allergic disorders. Novel chemical series from the most recent 2 years of patent literature have been reviewed. While overall structural diversity is moderate, these represent or relate to some of the compounds progressing through clinical trials (e.g., GSK-189254). However, an H(3) receptor drug still has yet to reach the market. Patenting activity is likely to remain high in the near future, bolstered by the commercial promise of potential H(3) receptor drugs.