The Medicines and Healthcare products Regulatory Agency (MHRA) said it had found two products, 'M2' and 'Energy 2000', on the market that may contain Strophanthus sarmentosus or Aristolochia species.
Aristolochia species have been banned in unlicensed herbal remedies in the UK since 2001. The plant can cause kidney failure and cancer, according to MHRA.
Strophanthus species have a powerful action on the heart and could result in serious heart problems including abnormal heart rate and heart failure.
The M2 herbal capsules are promoted to fight general infection, stomach disorders, fever, coughs and internal problems. Energy 2000 capsules are described as a sex restorative and for the treatment of piles and stress.