Two natural health supplements touted as sexual enhancement aids — Liviro3 and Zencore Tabs — may lead to serious heart problems and other side-effects, Health Canada warned.

The agency said it issued the warning because the capsules of Liviro3 contains the prescription medication Tadalafil, while Zencore Tabs contain an "undeclared pharmaceutical ingredient" similar to Tadalafil.

Tadalafil can lead to severe cardiac problems in people who have cardiovascular problems such as hypertension, or those who have had a serious heart arrhythmia, heart attack or stroke.

It can also cause side-effects including headaches, flushing, vomiting, diarrhea, and blood in the urine, among others.

Tadalafil is also not recommended for patients who are taking any type of nitrate drug therapy as it can cause potentially life-threatening hypotension.

Though Liviro3 is not authorized for sale in Canada, it is sold on the internet and Health Canada warned that travellers may bring it into the country.

Ebek Inc., the manufacturer of Liviro3, has recalled the product and has also said there is counterfeit Liviro3 on the market, warning consumers not to purchase any products under the same name.

Zencore Tabs is also not authorized for sale in Canada and the Canadian importer is currently recalling the product.

Health Canada advises consumers to only buy prescription drugs with a prescription from a doctor who has examined them in person, using a licensed pharmacy where they have an established relationship.

It also recommends that consumers look for an eight-digit Drug Identification Number (DIN), a Natural Product Number (NPN) or a Homeopathic Medicine Number (DIN-HM) on the label.

These numbers indicate that the products have been assessed by Health Canada for safety, effectiveness and quality.