Applied ethics is the philosophical examination, from a moral standpoint, of particular issues in private and public life that are matters of moral judgment. It is thus a term used to describe attempts to use philosophical methods to identify the morally correct course of action in various fields of human life. Bioethics, for example, is concerned with identifying the correct approach to matters such as euthanasia, or the allocation of scarce health resources, or the use of human embryos in research (see also Medical ethics). Environmental ethics is concerned with questions such as the duties of humans towards landscapes or species. Business ethics concerns questions such as the limits on managers in the pursuit of profit, or the duty of 'whistleblowers' to the general public as opposed to their employers. As such, it is a study which is supposed to involve practitioners as much as professional philosophers.
Applied ethics is distinguished from normative ethics, which concerns what people should believe to be right and wrong, and from meta-ethics, which concerns the nature of moral statements.
Much of applied ethics is concerned with just three theories. There is the quasi-mathematical approach of utilitarianism, where the practical consequences of various policies are evaluated on the assumption that the right policy will be the one which results in the greatest happiness; there are deontological notions based on 'rules' and an assumption that there is an obligation (that is a 'duty') to perform the 'right' action, regardless of actual consequences, epitomized by Kant's notion of the Categorical Imperative, and there is the increasingly popular theory of virtue ethics, derived from Aristotle's and Confucius's notions, which asserts that the right action will be that chosen by a suitably 'virtuous' agent.
There are of course many other approaches, some drawing on mathematical or psychological models, or on social and religious values, but the extent to which these appraoches are 'philosophical is a matter of debate. One such recent approach which attempts to bridge the divide between deontology and utilitarianism is case-based reasoning, also known as casuistry. Casuistry does not begin with theory, rather it starts with the immediate facts of a real and concrete case. While casuistry makes use of ethical theory, it does not view ethical theory as the most important feature of moral reasoning. The claim is that by focusing on cases and not on theory, those engaged in moral debate increase the possibility of agreement.