We assessed the effects of the extracts from Sabina vulgaris Ant., and two podophyllotoxin analogues, i.e., podophyllotoxin and deoxypodophyllotoxin, which are main insecticidal secondary components of S. vulgaris, on growth and food utilization of Mythimna separata larvae with weight method under treatment with three doses of AFC₃₀, AFC₅₀ and AFC₈₀. The results showed that the tested chemicals had obvious inhibiting activity on growth and development of M. separata larvae, and the larval stage was significantly longer when controlled with the three chemicals under above doses. During treated periods, the related growth rate (RGR) and related metabolizing rate (RMR) were significantly lower when controlled with the two podophyllotoxin analogues, and the higher the dose, the lower the rates. But in 3－5 days post treatment, these two rates recovered to common levels. The three chemicals had no obvious effects on larval approximate digestibility (AD). During the controlled period, the efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) significantly increased. In 3－5 days post treatment, these two rates also recovered to common levels. There was a certain extent difference of ECI and ECD among controlled chemicals, but no obvious difference among doses.