Patients diagnosed with a rising prostate-specific antigen level after radical prostatectomy represent a therapeutic dilemma. Herbal therapies including PC-SPES have gained popularity as alternatives to conventional hormonal ablation in such patients as a result of the perceived benefits of using natural products and proven clinical response in decreasing prostate-specific antigen levels. PC-SPES is one of the most popular herbs with known estrogenic activity in vitro and in vivo. Estrogenic compounds increase the risk of thromboembolic events. However, no specific guidelines are available with regard to the risk of thromboembolic events for patients using PC-SPES. We report a case of a patient treated with PC-SPES for prostate-specific antigen recurrence after radical prostatectomy who presented with pulmonary embolus and a right common femoral deep venous thrombus.