Acromegaly was the first pituitary disease to be recognised as a clinical entity, although initially it was not clear whether the eosinophilic adenomas causing pituitary enlargement were causative or just a manifestation of the syndrome itself. Following the documented clinical improvement of patients with acromegaly after partial hypophysectomy, it was proven that the pituitary adenomas were aetiological. The treatment of acromegaly has changed during the last decades; the introduction of the somatostatin (SMS) analogue octreotide has had major implications. Octreotide was the first SMS analogue to become available for clinical use. It is generally well tolerated, but is associated with the development of gallstones in 15 to 20% of patients. Other adverse effects include transient injection-site pain, abdominal, diarrhoea, gastritis (long term therapy) and loss of scalp hair. No long haematological or biochemical adverse effects have been reported. Desensitisation to the beneficial effects of octreotide therapy is highly unusual. A long-acting formulation of octreotide is being studied, and should be available by the end of 1997.