Almost half of complementary and alternative medicines are contaminated despite many being registered for use in Australia, according to Murdoch University research.

Reindeer fragments, banned drugs and paracetamol were among the non-listed ingredients found after testing 137 samples using DNA sequencing and mass spectrometry.

Nearly two-thirds of the products were on the Australian Register of Therapeutic Goods, and were purchased from Australian pharmacies, health food stores, traditional herbal retailers and online.

They ranged across traditional Chinese Medicine, and Ayurvedic and Western herbal medicines and supplements.