Mephedrone has been linked to at least four UK deaths
Hundreds of people attended a rally set up by a father who said his teenage daughter behaved like a caged animal after taking the legal drug mephedrone.
Mark McCall, from Bournemouth, says his daughter went missing for three days after taking the drug two weeks ago.
Mephedrone is said to have side effects similar to the drug ecstasy, which include psychosis, palpitations, nosebleeds and insomnia.
Mr McCall also launched his drug advice website at the Poole Quay event.
He told BBC News: "This drug has to be made illegal as soon as possible.
"I do not want to see my daughter in a box, I do not want to see anybody's daughter in a box."
Speaking of the incident when his daughter disappeared in March, Mr McCall added: "When we did find her, she was a mess,
"She was like a caged animal, she was all over the place."
Mr McCall's website, called The Save Our Kids Coalition, is aimed at advising and supporting families about drug use.
The Advisory Council on the Misuse of Drugs (ACMD) has recommended that the substance, linked to at least four UK deaths, and other so-called "legal highs" be classified as Class B drugs.
The government is expected to ban mephedrone and other "legal high" substances within weeks, following the advice of the ACMD.
Class B drugs, which include cannabis and amphetamine sulphate, carry a maximum sentence of five years in prison for possession or 14 years for supply.