The green algal coenocyte Caulerpa prolifera (Forsskal) Lamouroux was assayed for the presence of peroxidase using the benzidine and pyrogallol reactions, and for the presence of indole-3-acetic acid (IAA) using the Avena coleoptile test and a fluorescence assay. Growth studies using IAA were also carried out. The assays for IAA were negative. The growth studies showed a positive response to exogenous IAA (5 × 10−6 and 10−6 M). Similar concentrations of exogenous indole-3-butyric acid and indole-3-propionic acid completely stopped growth.