This article reviews and compares the incidence and toxicity, addiction potential, and dependence potential for each of the three types of inhalants. Despite the known toxicity of these substances, their use is on the increase. While there is clearly a potential for psychological dependence, it is yet unclear whether that dependence is due to the particular substance inhaled, the act of inhalation, or the social acceptance obtained through the activity. Physical dependence can be detected through signs and symptoms of withdrawal, although these vary with the patient and the abused substance. 59 references