The invention relates to the use of one or more cannabinoids, particularly THC and/ or CBD in combination with a non-cannabinoid chemotherapeutic agent in the manufacture of a medicament for use in the treatment of cancer. In particular the cancer to be treated is a brain tumour, more particularly a glioma, more particularly still a glioblastoma multiforme (GBM). The non-cannabinoid chemotherapeutic agent may be a selective estrogen receptor modulator or an alkylating agent.