Abstract Screening of aqueous extract of Phyllantus niruri (PL), Zingiber zerumbet (ZG), Eurycoma longifolia (TA-a and TA-b) and Andrographis paniculata (AP) to determine their blood glucose lowering effect were conducted in normoglycaemic and Streptozotocin-induced hyperglycaemic rats. Significant reduction in blood glucose level at 52.90% was shown when hyperglycaemic rats were treated with 50 mg/kg body weight (BW) aqueous extract of AP. This effect is enhanced when freeze–dried material was used, where 6.25 mg/kg BW gave 61.81% reduction in blood glucose level. In the administration of TA-a and TA-b, positive results in hyperglyacaemic rats were only obtained when 150 mg/kg BW of the aqueous extract was used. No significant reduction in blood glucose level were shown in hyperglycaemic rats treated with PL and ZG at all concentrations used (50, 100 and 150 mg/kg BW). In normoglycaemic rats, no significant reduction was noted when all the same extracts were used.