The Garda National Drugs Unit is investigating the manufacture and sale of a highly dangerous and addictive illegal street drug from over-the-counter common cold medicines.

The Health Service Executive and the Pharmaceutical Society of Ireland have both issued warnings to pharmacists.

They say some people are bulk buying products containing pseudoephedrine because they can be used to create methamphetamine, known as crystal meth.

Pharmacies in Dublin, Limerick and Kerry have also reported suspicious purchases of large quantities of the medicine Sudafed.

One man has been questioned and a file is being sent to the Director of Public Prosecutions following the discovery last month of a makeshift laboratory in Kerry.  

The small makeshift laboratory along with Sudafed tablets and around €8,000 worth of Crystal Meth was discovered in Tralee last month.

Gardaí discovered one man buying the tablets in Dublin who was a chemistry student at a third level institution.

Another pharmacist discovered that the same eight people were returning to buy two packets of pseudoephedrine medicine every day.

The PSI, the regulatory body for pharmacists, and the HSE have warned all chemists to be alert for suspicious and bulk purchases of pseudoephedrine medicines.