Diabetes is one of the serious metabolic disorders occurred due to the imbalance of glucose level because of damaged pancreatic β-cells and lower production of insulin in body. Type 1 Diabetes Mellitus (TD1) and Type 2 Diabetes Mellitus (TD2) are main types of diabetes. Major portion of the world is suffering from Type 2 diabetes mellitus. Drugs used for diabetes are insulin, biguanides, sulfonylurea and inhibitors for a-glucosidase. Traditional medicines are under trial to reduce diabetic complications with no/minimum side effects. Many antidiabetic plants are under potential research i.e. strawberry, jamun, mulberry, fenugreek, turmeric, black pepper, garlic, ginger, grapefruit, and cinnamon. All of these have antidiabetic potential. These plants have bioactive compounds present in minute amounts. These compounds act against inflammation, diabetes, bacteria, fungi, other microbial infections, and obesity. These plants have antioxidant potential as well. Through HPLC “High- Performance Liquid Chromatography” screening, the compounds identified were caffeic acid, isoquercetin, kaempferol and other flavonoids. These compounds showed hypoglycemic activity. They are responsible for the increased uptake of glucose by the adipose and muscle tissues due to the activation of specific receptors i.e. PPARa “Peroxisome Proliferatoractivated Receptors a” and PPARγ (Peroxisome Proliferator-Activated Receptor γ). These activate the enzymes like glutathione, glutathione-S-transferase and catalase. Glutathione peroxidase inhibits the a-amylase then a-glucosidase lower glucose level. Effect of phytochemicals present in antidiabetic plants were studied in vitro and in vivo in animal models by inducing diabetes in them by streptozotocin, alloxan and diet on diabetic patients. Types of phytochemical compounds and their composition vary due to environmental factors, extraction and separation techniques which can have effect on clinical analysis. Bioavailability of oral drugs was also studied synergistically with these plants. Synthetic drugs, if are used with these natural compounds, they have no harmful effect but increase effectiveness. These herbal medications are more preferable, safe to use and cost effective due to which it is easily affordable by people. This review report covers the impact of these plants on diabetes mellitus reported so far.