Torture can be defined as the infliction of physical or mental pain for interrogative or punitive purposes. Historically, it has been practised in various forms, but a tendency emerges towards abolition, notably in light of the progressive establishment of human rights and the invalidity of information collected by means of torture for evidential purposes. Currently, the prohibition of torture is universally acknowledged as an international non-derogable rule and the Convention against Torture strictly harmonises domestic law in order to implement this duty. However, despite such a thorough and compulsory regulatory system, the definition of torture remains ambiguous, particularly with respect to ill-treatment, and thus discloses room for discretionary implementation. Notably, ill-treatment is not subject to the same procedural requirements as torture. Within this context, both Western and Islamic States have developed a tendency to practice and legalise torture, specifically in the wake of 9/11 and the recent global escalation of terrorist attacks. In particular, Saudi Arabia and Iran prohibit torture as an investigative method, but legalise and implement it as a form of punishments prescribed in Sharia law. The United States and Israel generally prohibit torture as a form of punishment or investigation, but practice interrogative torture and try to legalise it in countering global terrorism. These practices are underpinned by the assumption that investigative techniques provoking physical or mental pain can be justified in situations of emergency, when they are necessary to save lives. A clash therefore arises between international and domestic law: is the domestic tendency to practice and legalise torture consistent with the absolute international prohibition or are new general principles of law emerging in the matter? Along the lines of cultural relativism, a systemic analysis of interactive regulatory layers, including international, Islamic, regional and domestic law, leads to the conclusion that the domestic tendency to practise and legalise torture is inconsistent with international law: no new legal principles are emerging. Under both particular and general international law, torture should thus be clearly defined and distinguished from ill-treatment, by absorbing the latter into the former, so as to exclude any margin of discretion with respect to the domestic practice of cruel and inhuman treatment.