Autoxidation of guaiazulene was examined in detail under the following conditions: in a highly diluted DMF solution, in DMF in the presence of acid or base (at 80–100 °C), and as solid state under sunlight or in the dark (at 25–50 °C). In all cases a wide variety of products were obtained (33 separable compounds altogether), and a comparable study on the distribution of the products under the various