Patients undergoing stem cell transplantation for the first time will be entered. Participants will be randomized to one of two study arms: Arm 1: intervention (routine care+ inhalation aromatherapy); Arm 2: Control (Routine care) Hypotheses: (1) Patients receiving inhalation aromatherapy will experience less severe nausea and less frequent vomiting episodes than those receiving only routine care; and (2) patients receiving inhalation aromatherapy will demonstrate lower anxiety levels just after AHSCT than those receiving only routine care.

Earlier research indicates that aromatherapy is promising to relieve in DMSO related nausea and anxiety in autologous stem cell transplant patients. The current study seeks to confirm and extend these findings in a 2-arm, open-label randomized, controlled study of 70 cancer patients undergoing autologous stem cell transplantation. All patients will receive a standardized premedication. Arm 1: Intervention (inhalation aromatherapy with orange essential oil during stem cell infusion); Arm 2: Control (routine care). The researchers hypothesize that inhalation aromatherapy with orange essential oil will be effective in reducing DMSO related nausea and vomiting and demonstrate lower anxiety levels just after autologous stem cell transplantation.

Inclusion Criteria:

• age > 18 years,
• the absence of any mental conditions including depression, anxiety disorders, psychotic disorders or dementia that may affect the patients' communication abilities

Exclusion Criteria:

• Patients with chronic obstructive pulmonary disease or asthma,
• a history of allergy to orange or orange essential oil,
• presence of persistent nausea and vomiting due to conditioning regimens,
• receiving antiemetic other than routine premedication,
• patients undergoing AHSCT for the second or more time were excluded