The Narcotic Control Act is the main body of drug legislation, and it contains a list of controlled substances under three categories: narcotics, psychoactive substances and cannabis. A list of controlled substances in the Narcotic Control Act contains not only individual drugs but also 12 groups of substances. They are: 

• Derivatives of morphine that have the structure of either Quaternary ammonium compounds or N-oxides;
• Analogues of fentanyl;
• Ecgonine and its derivatives;
• Analogues of phencyclidine;
• Methcathinone and its analogues;
• JWH-018 and its analogues;
• JWH-030 and its analogues;
• JWH-175 and its analogues;
• JWH-176 and its analogues;
• CP-47497 and its analogues;
• Barbituric acid and its derivatives; and
• Thiobarbituric acid and its derivatives. 

Analogues or derivatives that belong to the 12 main drug groups but are listed separately as individual controlled substances in the Act are exempted from scheduling of the drug groups.

In 2011, the Republic of Korea government introduced the temporary narcotics designation system to better respond to rapidly emerging new psychoactive substances. Substances designated as temporary narcotics are treated in the same manner with substances listed in the Act from the date of a pre-announcement for temporally scheduling, which takes place a month before an official announcement issued by the Ministry of Food and Drug Administration. In that regard, transporting, possessing, using, controlling, exporting, importing, manufacturing, trading, assisting in the trade of, giving or receiving temporary class drugs will constitute an offence according to the Act, and relevant substances can be seized by authorities from the date of a pre-notification for temporary scheduling. The period for temporary scheduling for substances is three years from the date of an official announcement during which the government can reclassify them as controlled substances in the Act based on the impact on the central nervous system and risks for dependence. Re-designation for substances once designated as temporary narcotics is also possible.

Between 2011 and 2020, a total of 221 substances were designated as temporary class drugs, and 115 were reclassified as controlled substances. The most recent temporary scheduling took place on 16 July 2021 for 17 substances, including AL-LAD, 25H-NBOMe, and U-48800.