The harm associated with high-risk injected opiate use and the threat of the HIV epidemic among injecting drug users has become a worldwide problem. Twenty years ago, in the face of a rapid increase in mortality rates among injecting drug users and the upcoming threat of HIV, the first harm-reduction programs were implemented in the Western world. This paper is a literature review describing four forms of harm reduction currently in use in Europe, North America, and Australia. Each represents a reasonable counterapproach to the threat of increased prevalence of HIV among injecting drug users in transitional and developing countries. The paper attempts to explain the concepts behind the most commonly used types of harm reduction and provides a brief overview of the advantages and disadvantages of each and the reasons for their implementation. The main focus of the review is on the definition and the practical aspects of harm reduction; it includes a brief introduction of Chinese harm-reduction efforts and their implications.