The present invention relates to the use of 2-[4-(4-chlorophenyl)cyclohexyl]-3-hydroxy-1,4-naphthoquinone or a physiologically acceptable salt or other physiologically functional derivative thereof for the manufacture of a medicament for the treatment of tumours in animals, to pharmaceutical compositions for the treatment of tumours in animals, to pharmaceutical compositions for the treatment of tumours, comprising said compound as active ingredient and to a method of treating tumours in an animal which comprises administering to said animal an effective amount of said compound.
