麦角酸是寄生于禾本科植物的多种真菌（麦角）所产生的次级代谢产物，属于麦角毒素的一种，是迷幻药麦角二乙胺（LSD）的前趋物。

Lysergic acid, also known as D-lysergic acid and (+)-lysergic acid, is a precursor for a wide range of ergoline alkaloids that are produced by the ergot fungus and found in the seeds of Turbina corymbosa (ololiuhqui), Argyreia nervosa (Hawaiian Baby Woodrose), and Ipomoea tricolor (morning glories, tlitliltzin). Amides of lysergic acid, lysergamides, are widely used as pharmaceuticals and as psychedelic drugs (LSD). Lysergic acid received its name as it was a product of the lysis of various ergot alkaloids.