Methylated soybean protein (MSP) and methylated β-lactoglobulin (MLG), previously confirmed for their antibacterial and antiviral activities, were tested for their potential toxicity in Wistar male Albino rats as one single dose (2,500, 5,000 and 10,000 mg/kg body weight) or as repeated daily dose (500 and 2,500 mg/kg body weight/day) over 28 days to assess potential toxicity. Single acute administration of very high doses (2,500, 5,000 and 10,000 mg/kg body weight) of MSP and MLG did not produce any mortality. Changes in body weight, organ weight, hematological parameters, histo-pathological images of selected organs, serum albumin, globulin and albumin/globulin ratio, cholesterol, triglycerides and electrolytes were all within normal amounts in the rats fed with these two methylated proteins and not significantly different from controls. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatinine and urea were slightly reduced by the administration of these two modified proteins indicating the absence of any adverse effect on hepatic or renal functions.