A mind-altering "magic mushroom" drug can safely improve the lives of patients with advanced cancer, it has been claimed.
Controversial research in the US showed that one session with the drug, psilocybin, improved mood and reduced anxiety in the patient group for up to six months.
Psilocybin is the active ingredient in "magic mushrooms", and classified as an illegal Class A drug in the UK.
The drug has psychedelic effects that can include the enhancement of colours and visual hallucinations.
Professor Charles Grob, from the LA BioMed research institute in Los Angeles, California, said: "We are working with a patient population that often does not respond well to conventional treatments.
"Following their treatments with psilocybin, the patients and their families reported benefit from the use of this hallucinogen in reducing their anxiety.
"This study shows psilocybin can be administered safely, and that further investigation of hallucinogens should be pursued to determine their potential benefits."
The pilot study involving 12 volunteers aged 36 to 58 builds on work in the 1950s and 1960s which found that psychedelic drugs could benefit advanced-stage cancer patients, reducing anxiety and the need for pain medication.
The early research was abandoned in the 1970s after a legal clampdown on the recreational use of hallucinogenic drugs such as LSD.
"Political and cultural pressures forced an end to these studies in the 1970s," said Prof Grob. "We were able to revive this research under strict federal supervision and demonstrate that this is a field of study with great promise for alleviating anxiety and other psychiatric symptoms."