Using a pharmacokinetic model based on drug concentrations in tissue fluids of normal animals, calculated withdrawal times were compared with the observations made in emergency‐slaughtered diseased animals. After multiplying the calculated withdrawal times for muscle and kidney cortex tissues by a factor of 2 to 3, and 4 to 5, respectively, a good estimate was obtained for predicting drug withdrawal times for diseased animals treated with beta‐lactam antibiotics, oxytetracycline, and aminoglycoside antibiotics. Criteria for determining three different drug tolerance levels of edible tissues were presented and discus