"No-effect-level" of malathion (o,o'-dimethyl dithiophosphate of diethyl mervaptosuccinate) in Bubalus bubalis.

An oral dose of 0.5 mg/kg/day malathion continuously administered for one year has been investigated to produce no change in biochemical (RChE, PChE, aspartate- and alanine aminotransferases, blood glucose, serum urea and plasma total proteins) or haematological (Hb, PCV, tRBC and tWBC) parameters and, therefore, considered to be "no-effect-level" in Bubalus bubalis. However, the administration of higher doses (1.0 and 1.5 mg/kg/day) produced significant (P less than 0.05) changes in all biochemical parameters studied. With these doses leucocytosis was evident among haematological parameters measured.