脱法ハーブ

Recently, there has been a lot of news about a narcotic substance in Japan. This substance is a herbal drug that is legal and on sale in some shops. I don't know what this particular herbal drug is but the name is rather amusing: dappo herb「脱法ハーブ」which can't be translated perfectly but I think these are possible translations:

• legal drug
• legal high
• legal weed

脱法 can be best translated as:

• legal loophole

This is a natural expression used in normal conversation.

ハーブ　＝　麻薬

In English, herb is a slang word for plant-type narcotic drugs, such as cannabis; I guess Japanese has adopted this slang.

I wonder if the media reporting has increased interest and sales in 脱法ハーブ。It's like stealth marketing（ステマ）。