The objective of this study was to elucidate the effect of Sterol Carrier Protein Inhibitors (SCPIs) on cholesterol transportation. We have identified several Sterol Carrier Protein Inhibitors (SCPIs) using high throughput screening (HTS). Those chemicals showed high larvicidal activities in the tobacco hornworm,Manduca sexta and can be classified into two types, depending on the timing of the acute toxicity. The "fast-killing" effect represented by SCPI-1 and the "slow-killing" effect typified by SCPI-2. SCPIs showed inhibitory effect on cholesterol absorption, but the speed of toxic activity was not correlated to the reduction of cholesterol absorption. The results indicate that the mode of action of each SCPI may be different.