2.2. Inclusion and exclusion criteria

The search was restricted to English and Persian language articles. All studies found during the search were independently evaluated for competence and inclusion by two different authors. After compliance with inclusion criteria, experimental research and clinical trials that evaluate the effect of medicinal herbs or plant component in diabetic animals or patients were included in the current research. Irrelevant studies or original article that evaluated mixed plant extract, algae, or mushroom extracts were also excluded.