The invention relates to three antitumour substances of plant origin, the combination of which is especially advantageous in the treatment of certain tumours, including malignant tumours. As far as the author is aware, none of these substances has ever been employed for this purpose. They are: 1. 6-Furfurylaminopurine, a molecule used in agriculture and marketed under the name ''kinetin'', or one of the variants defined below. 2. Indoleacetic acid or ''auxin''. 3. Lastly, gibberellic acid or one of the ''gibberellins'' known at the present time. The invention relates, in the second place, to the method of preparation of these substances, and lastly to the type of combination which it is appropriate to use in accordance with the tumour to be treated.
