Electrotopological state index for atom type (ETSIAT) was employed in the quantitative structure-activity relationship (QSAR) studies on the aliphatic alcohol toxicity to the Tetrahymena pyriformis, tomato, spider, bacterial luciferases, Fathead minnow, and rat. The QSAR models were established by partial least squares and further validated by both internal and external validations. The results showed that ETSIAT can characterize the structural information relevant to aliphatic alcohol toxicity very well and the QSAR models established have good stabilities and prediction capabilities. From the PLS (partial least squares) analysis on the QSAR models, it can be seen that hydrophobicity is the decisive factor to affect the aliphatic alcohol toxicity. The aliphatic alcohol toxicity was enhanced with increasing the length of carbon chain, and the aliphatic alcohol toxicity of straight chain was higher than that of branched chain with the equal number of carbon atoms. Due to the steric effect, there may be different toxicity mechanisms between long-chain and short-chain aliphatic alcohols.

Key words: quantitative structure-activity relationship, electrotopological state index for atom type, aliphatic alcohol, toxicity