What is international humanitarian law?
International humanitarian law is a set of rules which seek, for humanitarian reasons, to limit the effects of armed conflict. It protects persons who are not or are no longer participating in the hostilities and restricts the means and methods of warfare. International humanitarian law is also known as the law of war or the law of armed conflict.
International humanitarian law is part of international law, which is the body of rules governing relations between States. International law is contained in agreements between States – treaties or conventions –, in customary rules, which consist of State practise considered by them as legally binding, and in general principles.
International humanitarian law applies to armed conflicts. It does not regulate whether a State may actually use force; this is governed by an important, but distinct, part of international law set out in the United Nations Charter.
Where is international humanitarian law to be found?
A major part of international humanitarian law is contained in the four Geneva Conventions of 1949. Nearly every State in the world has agreed to be bound by them. The Conventions have been developed and supplemented by two further agreements: the Additional Protocols of 1977 relating to the protection of victims of armed conflicts.
http://www.icrc.org/Web/eng/siteeng0.nsf/iwpList2/Humanitarian_law:IHL_in_brief