The inhibition of neuraminidase from Clostridium chauvoei (jakari strain) with partially purified methanolic extracts of some plants used in Ethnopharmacological practice was evaluated. Extracts of two medicinal plants, Tamarindus indicus and Combretum fragrans at 100-1000 microg/ml, both significantly reduced the activity of the enzyme in a dose-dependent fashion (P < 0.001). The estimated IC50 values for Tamarindus indicus and Combretum fragrans were 100 and 150 microg/ml respectively. Initial velocity studies conducted, using fetuin as substrate revealed a non-competitive inhibition with the Vmax significantly altered from 500 micromole min(-1) mg(-1) to 240 micromole min(-1) mg(-1) and 340 micromole min(-1) mg(-1) in the presence of Tamarindus indicus and Combretum fragrans respectively. The KM remained unchanged at 0.42 mM. The computed Index of physiological efficiency was reduced from 1.19min(-1) to 0.57min(-1) and 0.75min(-1) with Tamarindus indicus and Combretum fragrans as inhibitors respectively.