Ilexonin A (Ile A) is an effective compound isolated from Ilex pubescens Hook et Arn which has been found to inhibit platelet aggregation and Ca2+ influx in platelets. The present experiments were designed to observe the effects of Ile A on platelet metabolism. Verapamil (Ver) was used as control. The results indicated that thrombin significantly reduced the level of platelet cAMP, while Ile A and Ver obviously antagonized this effect. The inhibition of the activity of platelet phosphodiesterase by Ile A was much stronger than that by Ver. The results suggest that Ile A may be beneficial in the treatment of cardiovascular disease.