Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plant hormone. Three classes of GA-biosynthesis inhibitors that affect different steps in the pathway are known.

Ancymidol is a pyrimidine-class plant cell endocrine disruptor plant growth regulator that interferes with gibberellin and cellulose biosynthesis. By inhibiting gibberellin biosynthesis, ancymidol reduces plant growth, resulting in reduced internode elongation and thus more compact plants. It is used in the commercial production of a wide variety of container-grown bedding and foliage plants, including chrysanthemums, Easter lilies and poinsettias. It has a role as a plant growth retardant, a cellulose synthesis inhibitor and a gibberellin biosynthesis inhibitor. It is a tertiary alcohol and a member of pyrimidines.