Commercially available isobutyl nitrite (iBN), n-butyl nitrite (nBN), sec-butyl nitrite (sBN) and tert-butyl nitrite (tBN) were found to be 63%, 79%, 44% and 96% pure, respectively, by GLC analysis. Pure samples of each compound were synthesized by the action of nitrous acid on each of the corresponding butyl alcohols; GLC analysis indicated greater than 99% purity for each nitrite. In determining LD50 values (mice, i.p.) for each compound, no deaths were observed after 30 min post-administration of sBN or tBN. Gross post-mortem examination suggests the delayed lethality may be due to liver damage. Administration of isobutyl, n-butyl, sec-butyl or tert-butyl alcohols to mice produced similar hepatotoxicity, suggesting that butyl alcohols may play a role in the hepatotoxicity observed after sBN or tBN administration.