Gibberellic acid is a hormone found in plants. Its chemical formula is C₁₉H₂₂O₆. When purified, it is a white-to-pale-yellow solution that is extremely harmful to organic substances, such as human tissue.

Gibberellic acid is a simple gibberellin, promoting growth and elongation of cells. It affects decomposition of plants and helps plants grow if used in small amounts, but eventually plants develop tolerance for it. Gibberellic acid stimulates the cells of germinating seeds to produce mRNA molecules that code for hydrolytic enzymes. Gibberellic acid is a very potent hormone whose natural occurrence in plants controls their development. Since GA regulates growth, applications of very low concentrations can have a profound effect while too much will have the opposite effect. It is usually used in concentrations between 0.01-10 mg/L.