BACKGROUND AND OBJECTIVES: The aim of this study was to investigate (1) the hydrocolloid properties of grass jelly on reducing glycaemic response, (2) the impact of phenolic compounds in Mesona chinensis L. on glycaemic response. METHODS AND STUDY DESIGN: A total of 15 healthy Chinese men were recruited to this study. On each visit, subjects consumed one of the following three treatments, i.e. glucose solution (T1), grass jelly (Mesona chinensis L.) solution with glucose (T2) or grass jelly gel with glucose (T3). Capillary blood glucose and venous plasma insulin were analysed over a period of 180 min. RESULTS: The incremental area under the curve for capillary glucose and venous plasma insulin for glucose group, grass jelly solution group and grass jelly gel was found to be statistically not significant (p>0.05). In a previous study the co-ingestion of grass jelly with complex carbohydrate was found to reduce glycaemic response. The key difference between the two studies was the use of monosaccharide glucose in the present study, compared to complex carbohydrates in the other. The present study suggests that the glycaemic lowering effect of grass jelly may be dependent on the inhibition of carbohydrase enzymes. CONCLUSIONS: The co-ingestion of Mesona chinensis L. appears to reduce glycaemic response of only complex carbohydrates through the inhibition of carbohydrase. This conclusion was arrived at by the lack of any effect of Mesona chinensis L. on the monosaccharide glucose.