A warning on the use of legal high substances has been reissued as police investigate a batch of potentially lethal tablets.
Between July and October, 13 people, including two teenage girls, have been admitted to hospital in the Strathclyde force area after taking Annihilation, which is sold in shops and online branded as a herbal incense.
Officers said they have also recently recovered a number of tablets that they believe to be 5-IT, a substance linked to several deaths in Europe.
Strathclyde Police would not say where or how many of the tablets were discovered but that they gave "real cause for concern".
Detective Sergeant Michael Miller said: "Rather than legal highs, we now tend to call them psycho-active substances. Another term is research chemical, and the clue is in the name as we don't know everything about it and the scientists don't know everything about it either.
"Basically they are created to mimic controlled drugs, whether cocaine or cannabis, by avoiding the chemical compounds detailed in anti-drug legislation, so they are constantly moving as the law changes.
"Because they are often sold in a packet and you can get them in some shops and online there is almost a legitimacy to them and people think they must be safe, even though it says on them 'not for human consumption'."
Annihilation is sold as a herbal incense but it is a synthetic cannabis that can cause a variety of side effects if consumed or smoked. Earlier this week the UK Government was urged to ban it by a council of drug experts.
Professor Les Iverson, chair of the Advisory Council on the Misuse of Drugs, described Annihilation as "particularly potent" and said its arrival showed how fast-moving the legal high market has become.
Superintendent Grahame Clarke said: "Our message is clear - people are using substances that haven't been tested, that have been designed in backroom labs and that can have quite drastic side effects. Our message is 'please don't misuse these substances'."