Ergoline is a chemical compound whose structural skeleton is contained in a diverse range of alkaloids including a few psychedelic drugs (e.g. lysergic acid and LSD). Ergoline derivatives are used clinically for the purpose of vasoconstriction (5-HT₁ receptor agonists—ergotamine) and in the treatment of migraines (used with caffeine) and Parkinson's disease. Some ergoline alkaloids found in ergot fungi are implicated in the condition ergotism, which causes convulsive and gangrenous symptoms.

In addition to the naturally occurring ergonovine (used as an oxytocic) and ergotamine (a vasoconstrictor used to control migraine), synthetic derivatives of importance are the oxytocic methergine, the anti-migraine drugs dihydroergotamine and methysergide, hydergine (a mixture of dihydroergotoxine mesylates, INN: ergoline mesylates), and bromocriptine, used for numerous purposes including treatment of Parkinson's disease. Newer synthetic ergolines used for Parkinson's disease include pergolide and lisuride.