The researcher will collect the data using Patient Information Form, Rhodes Index of Nausea, Vomiting and Retching Scale, Patient Diary for determining the number of nausea, vomiting, and retching episodes and the hours of breathing exercise of the patient, and Daily Nutritional Consumption Amount Form through face-to-face interview technique on the first day and for 14 days.

During chemotherapy and stem cell transplantation, antiemetic treatment included in the treatment protocol will be applied to the patients.

The patients will train about the application of breathing exercise by the researcher. They will be asked to do this breathing exercise with the guideline for at least 5 min in case of sensation of nausea and vomiting for 14 days.

The researcher will collect the data using Patient Information Form, Rhodes Index of Nausea, Vomiting and Retching Scale, Patient Diary for determining the number of nausea, vomiting, and retching episodes and the hours of breathing exercise of the patient, and Daily Nutritional Consumption Amount Form through face-to-face interview technique on the first day. The researcher will continue to fill out Rhodes Index of Nausea, Vomiting and Retching Scale, Patient Diary for determining the number of nausea, vomiting, and retching episodes and the hours of breathing exercise of the patient, and Daily Nutritional Consumption Amount Form for 14 days.

During chemotherapy and stem cell transplantation, antiemetic treatment included in the treatment protocol will be applied to the patients.

The exercise was applied in accordance with the "Guideline on Breathing Exercise for Reducing Nausea and Vomiting" prepared by the researcher in accordance with the literature. In addition, the researcher has a breath coaching certificate. The guideline include the application steps of breathing exercise. First, the researcher will demonstrate to the patients the practice of breathing exercise in accordance with the guideline. In the next step, patients they will be asked to do this application on themselves. The training is planned to take about 15-20 minutes for each patient. This guide will be given to patients after the training. They will be asked to do this breathing exercise correctly and effectively in accordance with the guideline for at least 5 min in case of sensation of nausea and vomiting for 14 days. The researcher will follow up the patients for 14 days by visiting room them every day.

Patient Information Form is a form prepared to determine the sociodemographic and disease-related characteristics of the patients. Sociodemographic characteristics of patient are composed of height, age, weight, educational status, social security, occupation, marital status, nutritional habits, smoking and alcohol use. Patient Information Form have general information about the patients such as diagnosis, duration, stage, and metastasis status of the disease, antiemetic drugs and treatment history. Disease history of cancer is , nausea-vomiting complaints before chemotherapy, the presence of any non-pharmacological method used to reduce nausea and vomiting induced by chemotherapy drugs.

Responses to each item are classified by using expressions appropriate to the item and scoring the severity of the nausea-vomiting-retching experience from 0 to 4. There are eight items in this scale that evaluate the experience, frequency and distress of nausea-vomiting and retching. The increase in score reflects worsening of the complaint experienced.

The amount of consumption of the patient in the morning, lunch, evening and snacks will be recorded before the treatment and throughout the study. The patient's antiemetic treatment, enteral and parenteral nutrition will be recorded daily in the follow-up form.