METHOD FOR ASSESSING PAIN CAUSED BY ADMINISTRATION OF DRUG SOLUTION, AND METHOD FOR SELECTING DRUG SOLUTION ADMINISTRATION 5 In a method for assessing pain caused by the administration of a drug solution, a rat (12) is provided, the rat (12) is anesthetized by inhalation anesthesia, a measurement electrode (24) is placed in the semitendinosus 10 muscle (12b) of the anesthetized rat (12), an injection needle (18) is punctured under the plantar subcutaneous (12a) of the anesthetized rat (12) while measuring the myoelectric potential in the semitendinosus muscle (12b) with the measurement electrode (24), a drug solution is 15 administered to the anesthetized rat (12) through the injection needle (18) after a myoelectric response caused by the punctuation of the injection needle (18) disappears, and at least one of the measurement of the duration time (T) of the myoelectric response caused by the 20 administration of the drug solution and the measurement of the EMG intensity, which is produced by integrating abso
