This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The aim of this review is to assess the effectiveness of Laetrile, as a sole or an adjunctive cancer therapy. Our primary question is 'does Laetrile prolong life or recurrences in patients with any type of cancer?'.

Our secondary questions are:

• Does Laetrile reduce tumor burden?

• Does it improve patients' quality of life (QOL)?

• Does it provide pain relief?

• Does it affect the efficacy of concomitant standard interventions?

• Compared to a standard intervention, does Laetrile have less severe side effects?

• Does Laetrile reduce tumor burden in cancer patients that, before Laetrile treatment, have not been treated with other interventions such as chemotherapy, radiotherapy, surgery or other cytotoxic drugs?