Scottish ambulance crews are dealing with six emergency call-outs every day on average as a result of so-called legal highs, an investigation has found.
There were 2,229 incidents involving New Psychoactive Substances (NPS) last year compared to just 150 in 2009, Scottish Ambulance Service figures show.
Doctors also said around 40 patients are visiting poisons units every month due to NPS.
The figures have come to light through a series of Freedom of Information requests by BBC Scotland.
A programme to be broadcast on Monday, BBC Scotland Investigates: The Deadly World Of Legal Highs, reveals that nearly half of all ambulance call-outs to legal high incidents are in the NHS Lothian area.
Figures published last week showed there were 114 deaths in Scotland where NPS had been taken - up from just four in 2009.
Community Safety Minister Paul Wheelhouse said the number was “unacceptable” but warned that it may not have reached its peak.
Dr James Dear, a clinical toxicologist at Edinburgh Royal Infirmary, told the BBC Scotland programme that legal highs now account for around 20% of admissions to its poisons unit.
He said: “One of the biggest poisons we see are legal highs. So we see around 40 or so patients per month, who come to our hospital, who are unwell because they’ve taken legal highs.
“Now most of the patients, typically, are agitated. They are acting bizarrely. It’s not uncommon for them to come in with the police. With two, three, four policemen, needing to be held down, needing to be sedated because they’re so unwell.”
He added: “We don’t have a routine way of identifying what drug this person’s taken in any kind of quick timespan.
“The stimulant effects can damage almost every organ in the body. So common problems would be kidney damage, seizures, high temperature, muscle injury, heart problems, all of these things can happen with legal highs. The dangers are there.”
In response to a series of FoI requests from BBC Scotland, the Scottish Ambulance Service searched its database for the names of more than 80 known brands of NPS, revealing the extent of their influence in call-outs.
The figures showed the majority of ambulance call-outs were recorded for NHS Lothian (1,063), followed by NHS Tayside (317), NHS Grampian (241) and 221 in the Great Glasgow area.