Rule 72. The use of poison or poisoned weapons is prohibited.

Practice

Volume II, Chapter 21.

Summary

State practice establishes this rule as a norm of customary international law applicable in both international and non-international armed conflicts. This prohibition exists independently of the prohibition of chemical weapons (see Rule 74). Although the Geneva Gas Protocol was inspired by the existing prohibition of the use of poison, there is sufficient separate practice establishing a specific rule on poison and poisoned weapons.

International armed conflicts

The prohibition of poison or poisoned weapons is a long-standing rule of customary international law already recognised in the Lieber Code and the Hague Regulations. “Employing poison or poisoned weapons” constitutes a war crime in international armed conflicts under the Statute of the International Criminal Court.

The prohibition of poison or poisoned weapons is set forth in numerous military manuals. The use of poison or poisoned weapons is an offence under the legislation of many States. This prohibition is also supported by official statements and reported practice. There is national case-law to the effect that the rule is part of customary international law.

In their submissions to the International Court of Justice in the Nuclear Weapons case, several States recalled the prohibition of poison and poisoned weapons. In its advisory opinion, the Court reaffirmed the customary character of the prohibition of the use of poison or poisoned weapons.