Health Canada and health officials in the US are warning consumers not to use PC SPES and SPES, two herbal products manufactured in the US by BotanicLab.

These products, designed to promote prostate and immune system health, were tested in the US by the California Department of Health Services and were found to contain active ingredients for the prescription drugs warfarin and alprazolam. These undeclared ingredients that could cause serious health effects if not taken under medical supervision.

Warfarin, a powerful blood thinner often sold under the brand names Coumadin, Taro-Warfarin and Apo-Warfarin can cause serious bleeding, especially if taken together with aspirin or certain other drugs, and thus should be used under a doctor's care with regular blood testing. Individuals who are currently taking anticoagulant drugs or have clotting or bleeding problems may be at increased risk of serious side effects.

Alprazolam is an anti-anxiety drug sold under various brand names in Canada. Alprazolam exacerbates the effects of alcohol and other sedating drugs and may be habit-forming.

Brea, California-based BotanicLab is recalling these products in Canada and across the US. In a statement on its Website, BotanicLab said further testing was necessary to determine whether the ingredient was warfarin or a natural compound that may mimic warfarin in laboratory tests.

The capsules are sold by mail, phone and Internet, as well as by various distributors and health care professionals.