This study was designed to examine the relationship between the antidiarrhoeal effects of Hange-Shashin-To (TJ-14) and its active components. Oral treatment with TJ-14 at 1000 mg/kg significantly inhibited castor oil-induced diarrhoea. Both the 50% methanol eluate fraction (fraction III) and the methanol eluate fraction (fraction IV) showed antidiarrhoeal effects at oral doses of 68 mg/kg and 63 mg/kg, respectively, corresponding to 1000 mg/kg of TJ-14. TJ-14 (1000 mg/kg, p.o.) showed a significant increase in blood corticosterone levels. Increased blood corticosterone was noted after the oral administration of 63 mg/kg of fraction IV. The inhibitory activity of TJ-14 on cyclooxygenase-2 (COX-2) was also observed in fractions III and IV. The main component of fraction III was Scutellariae Radixderived baicalin. Fraction IV contained Glycyrrhizae Radix-derived glycyrrhizin and isoliquiritin, Coptidis Rhizoma-derived berberine, coptisine and palmitine. Ginseng Radix-derived saponins were also present in fraction IV. These compounds inhibited castor-oil induced diarrhoea at oral doses of 10 or 30 mg/kg. Thus, the present results indicate that Scutellariae Radix, Glycyrrhizae Radix, Ginseng radix and Coptidis Rhizoma-derived components are involved in the antidiarrhoeal action of TJ-14.