The mainstream smoke contained methamphetamine (14.5 percent of the initial methamphetamine), phenylacetone (3.1 percent), N-cyanomethylmethamphetamine (1.9 percent), trans-B-methylstyrene (1.7 percent, N-formylmethamphetamine (1.5 percent), and other products (each greater than 1 percent). The amount of each pyrolysis product in the sidestream smoke was less than that in the mainstream smoke by a factor of over 5, except for methamphetamine (10.5 percent) and N-formylmethamphetamine (1.4 percent). The formation mechanism of these products was investigated, by use of a pyrolyzer, from the standpoint of the material, pyrolysis temperature, and pyrolysis atmosphere. Although several products (for example, dimethylamphetamine and trans-B-methystyrene) were formed by thermal self-decomposition of methamphetamine alone, most of the products, except N-cyanomethylmethamphetamine, were formed chiefly by the thermal reaction of methamphetamine with cigarette components. The formation of N-cyanomethylmethamphetamine required air and a high pyrolysis temperature. Air and a high pyrolysis temperature generally accelerated the formation of the pyrolysis products. 5 figures, 2 tables, and 11 references. (Author abstract)