HyoscineN‐butyl bromide (Buscopan) antagonized the spasmogenic action of acetylcholine on guinea‐pig isolated ileum, having a pA2of 7·8. The drug also had intestinal antispasmodic activity in the anaesthetized cat after either parenteral or enteral administration. With the enterally administered drug larger doses were required, but the effects were longer lasting. Enterally administered in conscious dogs the drug sometimes produced a small increase in heart