Categories of Precursor Chemicals

The 1988 UN Convention lists drug precursor chemicals in two tables. Table I contains substances which can be converted readily to controlled drugs or are essential for drug manufacturing. Table II contains other chemicals such as solvents and reagents commonly used for drug processing.

In the EU regulations, all of the chemicals in the UN Tables I and II are broken down into four categories based on the risk they pose balanced against their level of legitimate use. This difference allows a greater flexibility in the application of controls, checks and monitoring.

The EU regulations include additional precursor chemicals that have been used in illegal drug manufacture in the EU. Each category has differing requirements under the main pieces of legislation.

Category 1

Category 2

Category 3

Category 4

Category 1 contains substances that are readily convertible to controlled drugs, and are subject to the strictest controls.

Category 2 contains substances that are extensively used in the chemicals industry and which are also essential for drug processing.
Category 3 contains the reagents and solvents typically used in drug processing  

Category 4 relates specifically to medicinal products and veterinary medicinal products containing ephedrine, pseudoephedrine or their salts.


  • 1-phenyl-2-propanone (BMK)
  • Alpha-phenylacetoacetonitrile (APAAN)
  • Chloroephedrine
  • Chloropseudoephedrine
  • Ephedrine
  • Ergometrine
  • Ergotamine
  • Isosafrole
  • Lysergic Acid
  • N-acetylanthranilic Acid
  • Norephedrine
  • Piperonal
  • Pseudoephedrine
  • Safrole
  • 4-anilino-N-phenethylpiperidine (ANPP)
  • N-phenethyl-4-piperidone (NPP)
  • 3,4-methylenedioxyphenylpropan-2-one (PMK)
  • Methyl 3-(1,3-benzodioxol-5-yl)-2- methyloxirane-2-carboxylate (PMK methyl glycidate)
  • 3-(1,3-benzodioxol-5-yl)-2-methyloxirane-2-carboxylic acid (PMK glycidic acid)
  • Alpha-phenylacetoacetamide (APAA)
  • Methyl alpha-phenylacetoacetate (MAPA)
  • Methyl 2-methyl-3-phenyloxirane-2-carboxylate (BMK methyl glycidate)
  • 2‐methyl-3-phenyloxirane-2- carboxylic acid (BMK glycidic acid)

Subcategory 2A

  • Acetic Anhydride
  • Red Phosphorous

Subcategory 2B

  • Phenylacetic acid
  • Anthranilic acid
  • Piperidine
  • Potassium permanganate
  • Hydrochloric acid
  • Sulphuric acid
  • Toluene
  • Ethyl ether
  • Acetone
  • Methylethylketone (MEK)

Human medicinal products and veterinary medicinal products containing: ephedrine pseudoephedrine

The stereoisomeric forms of category 1 substances, not being cathine, whenever the existence of such forms is possible are also included. Additionally, the salts of category 1 substances, whenever the existence of such salts is possible and not being the salts of cathine, are included as well.

The salts of category 2 substances, whenever the existence of such salts is possible, are also included.

The salts of category 3 substances, whenever the existence of such salts is possible and not being the salts of hydrochloric acid and sulphuric acid, are included as well.