A new intravenous eugenol derivative, FBA.1420, has been studied as main anaesthetic for a standard operation (D & C) and the findings compared with those obtained using thiopentone, methohexitone and another eugenol derivative G.29.505. In many ways its action resembled that of G.29.505, and it caused less excitatory phenomena than methohexitone. Its cardiovascular effects were similar to those of thiopentone. Data on dosage requirements and recovery showed that both eugenol derivatives were less cumulative than barbiturates, but did not differ from each other in this respect. They also both caused more emetic sequelae than the barbiturates. In view of the smoothness of anaesthesia, with minimal complications and the extreme rapidity of recovery, even after large doses, FBA.1420 is worthy of a more extended clinical trial.