Research in the field of histamine receptors over the past 100 years went hand-in-hand with the development of modern pharmacology. Advances in histamine research led by outstanding scientists was so incisive that the clinical approach to treat allergies and gastrointestinal ailments was revolutionized. The pharmacological treatment of peptic ulcer and gastroesophageal reflux was indeed a revolution, as it ended the surgical intervention. Interest in histamine pharmacology was resurrected by the discovery of another histamine receptor, number 4, using genomics-based reverse pharmacological approaches for screening orphan GPCRs. This receptor is preferentially expressed by immune cells and its discovery raised hopes for its translational exploitation as a new therapeutic target for unmet medical needs ranging from asthma to cancer. However, several drawbacks emerged and dramatically slowed down research in the field. The development of new histaminergic ligands is an ongoing process that constantly provide new preclinical tools. weiterlesen