The health ministry will file a criminal complaint against a Tokyo-based importer for allegedly selling a chemical whose effect is similar to that of illegal drugs, ministry officials said Wednesday.

The stringent move came after the company failed to follow the ministry's instruction in October not to sell the drug Rush (isobutyl nitrite), claiming it is imported as a "video head cleaner, not a drug."

Rush, which is increasingly being abused by young people in Japan, has fallen into the category of drugs collectively called "dappo" (law evading) partly because it includes pharmaceutical ingredients, and it is not designated as a narcotic.

The drug, a liquid mainly sold in a 12-milliliter bottle, makes blood vessels get bigger and can be life-threatening. It is said to create a feeling of euphoria and enhance sexual pleasure.

The Health, Labor and Welfare Ministry has virtually regulated the manufacturing and selling of drugs in this gray zone if they can be regarded as violating the Pharmaceutical Affairs Law. This is determined by evaluating such circumstances as how and where they are sold.

The importer, based in Shinjuku Ward, Tokyo, has been importing Rush from the United States for nearly 20 years in batches of 10,000 bottles, ministry officials said.

It has paid about 200 yen per bottle and sold them to variety stores or sex shops at about double the cost, they said.

The ministry told the company in October not to sell the drug and ordered it to report on the drug's purpose, how much it imports and where it is sold. But the company did not take any action to recall the product, they said.