Subclinical mastitis caused a rise in the noncasein protein concentration of milk. This mainly was caused by an increase in the concentration of serum albumin and immunoglobulin derived from blood. In most cases, the concentration of the major whey proteins beta-lactoglobulin and alpha-lactalbumin decreased. This decrease can be attributed to both inflammatory damage of mammary secretory tissues and destruction of blood-milk permeability barriers. When used orally, levamisole reduced leukocyte count and intramammary pathogens. Although changes of concentration were least for relative amounts of beta-lactoglobulin, serum albumin, and immunoglobulin, we observed enhanced alpha-lactalbumin production and simultaneous reduction of the total whey protein as mastitis score decreased. In normal quarter milk, the relative amount of immunoglobulin increased with levamisole. This suggests there was increased transport of immunoglobulin to aid udder health.