Zhou C 2001.

Methods	Generation of allocation sequence: unstated. Blinding: not used. Sample size estimation: no information. Withdrawal/drop‐out: unstated.
Participants	Ethnic: Chinese; 300 patients (200 in treatment group, M/F 87/113, mean age 49 years (32‐68), mean disease duration 4.7 years; 50 in control group I, M/F 18/32, mean age 47 years (31‐70), mean disease duration 5.1 years; 50 in control group II, M/F 19/31, mean age 48 years (29‐68), mean disease duration 4.5 years). Setting: outpatients and inpatients. Inclusion criteria: type 2 diabetes mellitus, diagnosed by WHO criteria (WHO 1999), without recently developed severe complications. Exclusion criteria: not stated.
Interventions	Experimental intervention: Jiangtang No. I, II, III (3 different herbal mixtures) capsule, 4‐6 capsules daily, No. I, II, III orally before breakfast, at lunch and dinner respectively; for 2‐4 months. Control interventions: ‐ Control group I: glibenclamide, 7.5‐15 mg daily, orally, t.i.d., for 2‐4 months. ‐ Control group II: Jinqi Jiangtang capsule (herbal medicine), 7‐10 capsules, t.i.d., orally, for 2‐4 months. All patients from three groups received education on diabetes, dietary control and suitable exercise.
Outcomes	Symptoms and FBG. No follow‐up was reported.
Notes	No explanation for the skew distribution of patients between groups.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear