This study describes the antidiarrhoeal and bronchodilatory activities of Valeriana wallichii D.C. (Valerianaceae). The crude extract of V. wallichii (Vw.Cr) caused inhibition of castor oil-induced diarrhoea in mice at 300-600 mg kg⁻¹. In guinea-pig trachea, Vw.Cr concentration dependently (0.03-3.0 mg mL⁻¹) relaxed the low K+ (25 mM)-induced contractions, with a mild effect on the contractions induced by high K+ (80 mM). In the presence of glibenclamide, the relaxation of low K+-induced contractions was prevented. Similarly, cromakalim caused glibenclamide-sensitive inhibition of low K+, without any effect on high K+. These results indicate that V. wallichii exhibits antidiarrhoeal and bronchodilatory activities, possibly through K+ channel activation, and thus reveal its medicinal usefulness in hyperactive gut and airway disorders such as diarrhoea and asthma.