Amazon appears to have growing troubles around herbal supplements sold on its site.

The online retail giant has informed the herbal supplement company Celebrate Today (Brentwood, New York) that its Red Mammoth pills were tainted with sildenafil and tadalafil, both of which are FDA-regulated drugs for erectile dysfunction and other conditions.

Similarly, Amazon announced that a lab identified tadalafil in the “Red Pill” capsules from a company known as Your Favorite Shop (Jackson, New Jersey). FDA also announced that a company known as Positive-Health (Wilmington, Delaware) is voluntarily recalling a lot of supplements with undeclared tadalafil.

FDA has announced that Positive Health, Celebrate Today and Your Favorite Shop are carrying out a voluntary nationwide recall of the pills.

Last week, FDA announced several similar recalls affecting supplements sold on Amazon.

A press release from the FDA notes that the PDE-5 inhibitors sildenafil and tadalafil have been associated with drug-drug interactions. For instance, individuals with metabolic disease taking nitrates such as nitroglycerin may suffer potentially life-threatening drops in blood pressure when taking PDE-5 inhibitors. Heart patients combining PDE-5 inhibitors and nitrates also may face an elevated risk of heart attacks.

In 2020, FDA warned that supplements sold on sites such as Amazon, eBay and other virtual retailers may have an elevated risk of containing undeclared drug ingredients.