There is no herbal cure for diabetes. Some herbal remedies that may be of use in treating diabetes include fig leaves, black seed, fenugreek, cinnamon, grape seed extract, olive oil and bitter melon, according to Natural News. Studies have shown that cinnamon, in particular, improves the body's metabolism of sugar, triggering the release of insulin, as reported by WebMD.
Clove oil extracts have also been useful in improving insulin function and lowering glucose, total cholesterol, LDL and triglycerides, according to WebMD.
Although scientific evidence is lacking, some people with diabetes have experienced improvements in their condition after drinking a tea brewed from chopped avocado seed or apple chunks. Reports suggest improvements may be experienced after 2 weeks with the former and 2 months with the latter.