Recombinant alpha-interferons are used as therapeutic agents in an increasing number of benign and malignant disorders. Long-term administration of recombinant alpha-interferon as a maintenance agent is associated with a small number of adverse side-effects which are responsible for patient intolerance of this drug. These include weight loss, alopecia and chronic fatigue, anorexia and depression syndrome. This latter syndrome needs to be distinguished from thyroid disease, which is documented in this report in a number of patients on recombinant alpha-interferon therapy.