In treating diabetes over the long term, controlling the daily life is very important and cannot be neglected. In particular, the patient’s awareness and practice of their treatment had a great influence on their treatment. However, there has been very little scientific research done with regard to how much the patient understands the instructions about taking their medicine and whether they actually follow those instructions. Due to these facts, in this research we studied what guidance should be given when taking medicines made from insulin after analyzing the results of an investigation taken from the patients’ point of view. In carrying out a study on the education and the degree of understanding of insulin selfinjections, it became clear that older patients’ ability to understand diminished, and the patients forgot to shake the NPH insulin immediately before injection. And, in more than a few cases, even when the NPH insulin was shaken, injections took place after some time had passed. After studying the amount of time that elapses once sedimentation begins, it was found that the insulin is effective if it is injected within 2.5 minutes of being shaken. Next, a study was carried out on the problems of maintaining the quality of life (QOL) of patient while continuing the treatment for diabetes. As a result, it became clear that the patient’s lifestyle, including psychological factors, exerts a large influence on continuing the correct treatment. In particular, in cases of insulin injections when the patient eats out, younger patients tend to be more susceptible to psychological influence. This suggests that there is a need to work on guidance for the patient in taking their medicine. And, such guidance should strictly adhere to information regarding the patient’s lifestyle, which comes through good communication with the patient. On the other side, the coring of the insulin vial of insulin was examined in terms of medicine production technology. As a result, the occurrence of coring is seen irrespective of the type of needle and the temperature of the rubber vial stopper, and the fact that rubber fragments were found in the injection solution, suggesting the possibility of subcutaneous rubber fragments through injection. Further examination of the problems of continued long-term treatment of injected medicines may be necessary in the future. Due to the necessity of self-control of patients and the long time span of treatment that is involved, maintaining the QOL of the patients is important in diabetes treatment. We feel that it is important to give guidance about treatment, which fits the patients’ lifestyles.