2 September 2010 Last updated at 15:14 GMT
A man, 48, and woman, 46, were arrested in Dartington after police searched their property on Wednesday.
A substance which is believed to be Ayahuasca, and contains the Class A drug DMT, was seized at the property.
Ayahuasca is a psychoactive drug used by the South American Santo Daime Church, which one of the detainees claims to be a senior member of.
Both have been released on bail until 1 December.