Is it true that gumbi gumbi can be helpful in treating cancer? Has anyone else heard this, or even tried it?"

Gumbi gumbi (or gumby gumby) is otherwise known as the native Australian plant Pittosporum Phylliraeoides. Gumbi Gumbi is a medium to large tree, native to certain areas of Australia, and very sparsely found. Many people believe there are up to six varieties, with only one having medicinal properties used in Aboriginal herbal remedies and another being toxic. 

The major constituent of gumbi gumbi extract is saponin (a sulphonated di- or tri-terpene). Saponins are natural detergents found in plants. They’re highly toxic to cold blooded animals and some have been identified in snake venom, starfish and sea cucumber. Some are toxic to humans. Also present in gumbi gumbi extract are tannins, which have shown potential antiviral, antibacterial, long-term antioxidant and anti-parasitic properties. There are also alkaloids, naturally occurring chemical compounds containing basic nitrogen functionality that have pharmacological effects at low doses and are used in medications and recreational drugs. There is no credible independent scientific evidence that gumbi gumbi extract has any effect on cancer.