Vernonia amygdalina (VA) extracts have been reported to possess antioxidant and hypoglycaemic properties in animal studies with paucity of data in human study. To bridge this gap, this study investigated the effect of 8 weeks supplementation of freeze-dried VA leaves on glycaemic indexes and oxidative stress biomarkers in Type 2 diabetics with or without foot/leg ulcer and compared with non-diabetics with or without chronic foot/leg ulcer. One hundred and twenty participants were recruited and grouped into four. Each group was randomly divided into 3 subgroups: subgroup-1 (250 mg VA); subgroup-2 (500 mg VA) and subgroup-3 (No supplementation, NS). Ten millilitres of fasting blood samples were collected for determination of fasting plasma glucose (FPG), glycated haemoglobin A1c (HbA1c), total plasma peroxides (TPP), total antioxidant status (TAS), oxidative stress index (OSI), antioxidant micronutrients. Also, the wounds were clinically assessed and rated (WA) using modified ABDEFS. Statistical significance was considered at p<0.05. In the subgroups supplemented with 250 and 500 mg VA for 8 weeks, decreases in FPG, HbA1c, TPP, OSI and improvement in WA (p<0.05) as well as increases in TAS and antioxidant micronutrients (p<0.05) were found in all the groups. However, in NS subgroups, increases in FPG, HbA1c, and worsening of wounds (p>0.05), TPP, OSI (p<0.05) with significant decreases in TAS and antioxidant micronutrients were observed. Supplementation with Vernonia amygdalina could be used as a potential adjunct for treatment of diabetes mellitus and diabetic foot ulcer, but with caution when used as prophylactic in non-diabetics to prevent occurrence of hypoglycaemia.