I know this sounds ridicoulous but some people are claiming that you can get high smoking banana peel
Is it true?
And if it is how does it work?
Bananas contain no known psychedelic substances, so any "high" that is experienced is purely psychological.
The book Rooted in America: Foodlore of Popular Fruits and Vegetables gives a short overview over the topic:
For a few months in 1967 bananas made he headlines as the latest ingredient for a psychedelic trip. Underground newspapers in Berkley, New York, and Los Angeles published instructions for drying the fiber from banana peels to be rolled in a joint or in a pipe and spoked. It was called Bananadine or Mellow Yellow. Scientists at the University of California at Los Angeles, at New York University, and at the National Institute of Mental Health analyzed banana fiber and the effects of banana smoking. They concluded that the effects were psychological rather than pharmacological. The Federal Drug Administration reported extensive testing that turned up no evidence of hallucinogens in banana smoke.
One of the published papers rejecting the idea that bananas contain psychedelic substances:
The recent practice of smoking dried banana scrapings to achieve a "psychedelic experience" led the authors to investigate the hallucinogenic properties of bananadine, or "mellow yellow." They conclude that the "active ingredient" in bananadine is the psychic suggestibility of the user in the proper setting. Bozzetti, Ungerleider & Goldsmith: The Great Banana Hoax
Another published paper states:
Studies have revealed that the baked skins do not contain significant amounts of any known hallucinogen. A. D. Krikorian: The Psychedelic Properties of Banana Peel: An Appraisal
It goes on citing the FDA analysis which reached the same conclusion. The papers conclusion is phrased a bit weaker though:
Although the effects of banana smoke have turned out to be more psychologic than psychedelic, the fact still remains that banana peels, like all other plant tissues, contain countless unidentified substances.