Legal highs 'tried by 12-year-olds' say drug workers
31 January 2014 Last updated at 19:07 GMT
Children as young as 12 are trying chemicals which mimic the effects of cannabis and ecstasy.
That is according to the Gwent Drug Intervention Programme which says so-called legal highs are a growing problem.
Sold in brightly coloured packaging, most are not covered by drugs laws because they are chemically different to their illegal counterparts.
A Welsh government scheme is trying to address the problem by analysing substances for free and publishing the side effects on the internet.
Paul Heaney reports.