Plumstead High Principal Craig George has warned parents and other educators to be on the look out for the use of cough syrup cocktails by school children.
He suggests that the concoction often referred to as "sizzurp", "purple drank", "lean" or "syrup" is on the rise in local schools.
Codeine-based prescription cough syrup is mixed with cooldrinks (typically Sprite) and often sweets, resulting in a high.
According George, school children using sizzurp tend to be drowsy, have a lower attention span in class or experience extreme highs and lows.
He says that pharmacists in southern suburbs area have noted an increase in demand of cough mixture from local youth.
Pupils arrive at school with their own camouflaged Sprite cooldrink bottles, adding cough syrup and asprin tablets, George explains.
He has urged parents to monitor any changes in behaviour, dress code or language of children, and be vigilant for any empty cough mixture bottles in bins.
Listen to the full conversation from CapeTalk's Breakfast with Kieno Kammies: