Adverse effects and tolerance to dry powder of aerial part of Andrographis paniculata (Burm.f.) Nees were studied in 20 patients with type 2 diabetes mellitus for a period of 12 weeks. Patients were given powdered A. paniculata starting with 600 mg daily, gradually increasing to a maximum of 1.8 gm daily. Parameters monitored included body weight, blood pressure, liver function tests, renal function tests, cardiac enzymes, haemogram, serum electrolytes, fasting blood glucose, HbA1c, blood cholesterol, serum triglycerides and blood hormone levels (triiodotyronine, thyroxine, thyrotropin, insulin, fasting cortisol). None of the above mentioned parameters showed significant change during the study period except for a fall in HbA1c by 5.46%(p