The Health, Labor and Welfare Ministry is analyzing the composition of hallucination-inducing mushrooms, known as magic mushrooms, in a bid to tighten laws over their use, a health ministry research group said Tuesday.

The ministry said it is considering adding the mushrooms to items that are subject to the Narcotic Control Law, which would prohibit possession and obtainment.

Thirteen kinds of the mushrooms, the possession and usage of which are currently lawful, grow naturally in Japan, the research group also said.

The mushrooms in question contain hallucinogenic substances, such as psylocybin. Extracting the substances from the mushrooms is against the law.

However, the mushrooms are legally sold via the Net and at stores in entertainment districts.

A series of accidents involving magic mushrooms have occurred this year, the group says.

A man believed to have consumed a mushroom grown at his home froze to death in Akita Prefecture in January, and actor Hideaki Ito was hospitalized after experiencing hallucinations believed to have been caused by massive consumption of magic mushrooms in April in Tokyo.

A rapidly increasing number of people are seeking advice about the mushrooms by contacting the Japan Poison Information Center in Tsukuba, Ibaraki Prefecture.

The center has confirmed that the 13 kinds of mushroom comprise seven types of strophariaceae, four of coprinaceae, and one each of amanitaceae and cortinariaceae. Those being traded in Japan include copelandia cyanescens, a type of coprinaceae.

Other varieties of magic mushrooms are available on the foreign market.

The ministry research group said it is necessary to inform the public that excessive consumption of the mushrooms can lead to poisoning.