MORPHINE - the drug hip-hop star Molemo "Jub Jub" Maarohanye tested positive for - is highly dangerous and addictive, medical experts say.
After the horror crash last week, which left four pupils dead, Jub Jub tested negative for alcohol but his urine tested positive for morphine and cocaine.
Maarohanye's co-accused, Themba Tshabalala, tested 0,4percent for alcohol - well over the legal limit. His urine also contained traces of cocaine and morphine.
Leonie Kason, medical manager at the South African National Council on Alcohol and Drug Dependance, said morphine was a "schedule seven" painkiller.
"It's not a common drug that you find in the streets like cocaine and heroin. It can only be bought with a doctor's prescription. But we think people are able to forge the (necessary) documents and acquire it at pharmacies.
"Morphine is given as an injection to patients with severe pain - like those suffering from cancer and who are at a terminal stage. It is also given to patients who have just had operations - as a painkiller."
Morphine made one sleepy, decreased the heartbeat and slowed down the user's reflexes, Kason said.