The poster says on Facebook: "I'm gonna post up a video this is just to aware all the whanau out there what drugs do to you, I know a lot of people won't agree that I put it up cause it is my sister but I don't care, I'm [f******] sick of seeing our youth do this [****] and tired of our youth doing nothing better ... sorry."
It is not clear what the pair have taken, but on the video the man says: "Update: Its basically bath salts which is synthetic stimulants but it could be spice which is synthetic marijuana. Either way both do the same thing."
Spice is a synthetic cannabis and is extremely potent. It is at the centre of an epidemic across the UK and US, with many pictures showing users slumped on pavements, in cars and in trance-like states, leading it to be described as a zombie drug.
It was reportedly innocently invented by an American scientist examining the effects of cannabis on the brain.
Massey University drugs researcher Associate Professor Chris Wilkins said "bath salts" and "spice" were vague terms so it was difficult to know what the products contained.
"One of the risks is that when you buy products that are sold to you as 'spice' it can actually be a whole range of different synthetic cannabinoids, some of which are really dangerous.
"If someone sells you 'bath salts' it usually means they don't have any idea what it is. It could be anything.
"That's the real danger.
"Often even the seller doesn't know what they are selling and the risks can range from moderate to really serious; emergency situations.
"People should be careful. The best advice is don't buy them and don't use them."
Drug Foundation executive director Ross Bell said "bath salts" could be one of a number of different compounds, some of which were dangerous.
The name came from their appearance: white crystals that some said looked like bath salts. The foundation refers to them as "mysterious white powders".
Two of the mysterious white powders the foundation is aware of are:
• Mephedrone - a stimulant that is chemically similar to amphetamines and produces effects like those of Ecstasy, cocaine and amphetamines.
• Alpha-PVP, also called gravel, flakka or niff - the foundation says a study had found it acted as a "stimulant for rats and that their behaviour became increasingly bizarre at higher doses".
Bell said alpha-PVP, often sold as Ecstasy, caused the death of a 23-year-old in New Zealand in 2015.
In addition to nausea and vomiting, bath salts could cause serious physical and mental effects, including paranoia, hallucinations and anxiety.
"Then when you mix it with alcohol, that amplifies the problems."
Drugs known as "synthetic cannabis" were just as dangerous as bath salts, Bell said.
They were simply new chemicals. Their effects were nothing like natural cannabis and
often nothing like the synthetic cannabis products that were sold legally in New Zealand shops until banned by the Government.
