This chapter discusses how virtual worlds (VWs) have been and are being used for the prevention and treatment of addictive behaviors related to substance abuse. The substances covered are tobacco, alcohol, and illegal drugs. By definition, physical health concerns the body but there is an indisputable physiological component to mental health (for example, vitamin D is related to depression). I suggest that embodiment – as a distinctive characteristic of VWs when compared to other virtual spaces (e.g.: chatrooms) - should present great potential for health professionals when considering VWs for the design of prevention or treatment health programs. VWs free users of time and space constraints. This further justifies the use of VWs as alternative or complementing spaces of intervention. The anonymity of these environments reinforces this idea, as addictions that were socially acceptable just a few years ago have become socially stigmatizing (e.g.: smoking). In the case of virtual worlds such as Second Life, anonymity is combined with embodiment, and this compounded effect, which is anything but simple, is particularly important for health professionals and health promotion advocates interested in exploring the use of virtual worlds in the treatment of substance abuse.