The purpose of this study was to investigate the effect of behavior therapy on nausea, gagging and vomiting in pregnancy. 50 pregnant women referred to Imam Khomeini Hospital and Touba Specialized Clinic in the Sari city , at 6-12 weeks of gestational age, moderate and severe nausea and vomiting complaints and single pregnancy were enrolled and non-randomly assigned to the intervention and control groups. Hospitalized mothers, mothers with digestive disorders and thyroid disorders, as well as mothers with high risk pregnancies were not included in the study. Behavioral therapy sessions were conducted for the intervention group in 6 sessions of 50 minutes (for 2 weeks), in which techniques such as self-monitoring, relaxation, stimulant control, and systematic desensitization to mothers were taught. Study was not blinded. The PUEQ questionnaire was filled out by subjects for measuring nausea and vomiting and gagging immediately and 1 month after intervention. Outcome variables: Duration of nausea, vomiting frequency, gagging frequency