The stimulatory effect of feeding sucrose and sinigrin was studied with Vth instar larvae of Schistocera gregaria (Orthoptera). The food consisted of filter paper impregnated with the phagostimulant dissolved at different concentrations in water. We studied the intake of filter paper and phagostimulant simultaneously and separately. The intake of sucrose or sinigrin-impregnated paper gradually increased up to a limit, depending on the concentration of the phagostimulant, then decreased. When the intakes of paper and of phagostimulant were studied separately, they evolved differently: phagostimulant intake remained constant at the highest concentrations as filter paper intake decreased. The stability of phagostimulant intake suggested regulatory processes whose nature has been discussed. The results with the two phagostimulants were comparable; however, they were obtained with lower amounts of sinigrin than of saccharose. There was no dissuasive or toxic effect even at every high concentrations.