A teenager was left fighting for his life after reportedly taking the legal high mephedrone.

The 19-year-old’s illness led police to repeat their warnings to young people about the dangers of the drug, also known as meow and MCAB, which has similar effects to cocaine and ecstasy but is sold as plant food.

It follows reports from doctors in Brighton of steady rise in the number of people they treat who have fallen ill after taking the drug.

The teenager fell ill at his home in Sayers Common, near Burgess Hill, last Wednesday, and was rushed to Princess Royal Hospital in Haywards Heath.

He was treated in intensive care but his condition has since improved.

A 21-year-old man was arrested on suspicion of supplying a class A drug. He has been released on bail until April 10 while police investigate further.

The Advisory Council on the Misuse of Drugs is investigating whether mephedrone and five similar substances should be banned.

Mephedrone is sold over the counter or on the internet for as little as £5. Drugs experts have raised concerns the fact it is not illegal could be confusing people into assuming it is safe.

Sergeant Simon Alexander of Sussex Police said: “The phrase ‘legal high’ is misleading and to a large number of people especially young people, indicates that something has been approved for use and is perfectly safe.

“This is clearly not the case. Many household cleaners and other substances used in the home and in industry carry health warnings about appropriate use and would be clearly dangerous if ingested but they are not illegal to possess.

"Mephedrone may seem like a harmless bit of fun but the implications could be deadly. The biggest dangers with so called ‘legal highs’ are their unknown qualities.”

Police have warned users of the drug they could be arrested and their homes searched even though the drug is available legally.

Senior officers said people wity suspicious substances face arrest on suspicion of possession of controlled drugs until tests can show exactly what they are carrying.

Anyone with information about drug-dealing is asked to call Sussex Police on 0845 6070999 or Crimestoppers anonymously on 0800 555111. Information about drugs is available at www.talktofrank.com.