Inclusion Criteria:

1. Person is over the age of 20 but not older than age 45.
2. Person is willing to participate as evidenced by signing the written informed consent form.
3. Suffers from known dominant severe symptom of breast swelling and tenderness (level 7-10 according to standard scale of PMS symptoms severity)
4. Other severe symptoms of Premenstrual syndrome (based on WHO and ACOG criteria). This may include one or more of PMS symptoms with level 7-10 according to standard scale of PMS symptoms severity.
5. At work, school, home, or in daily routine, at least one of the PMS symptoms caused reduction of productivity or inefficiency
6. At least one of the PMS symptoms caused avoidance of or less participation in hobbies or social activities

7. At least one of the PMS symptoms interfere with relationships with others:

   i. Timing of PMS symptom(s): during the 14 days prior to onset of menstrual flow (rather than spotting) and up to 5 days during the menstrual flow. ii. Pattern and length of PMS symptomatic period: minimum of 2 days, up to 14 days.

iii. For PMS diagnosis two out of last three consecutive menstrual cycles were monitored by daily monitoring of symptoms.

iv. Timing and length of asymptomatic phase: day 6 to at least day 10 of the menstrual cycle.

v. Cyclicity - presentation of the 'off-on' phenomenon: there should be a clear shift from no PMS symptoms to PMS symptoms.

vi. Reliable non hormonal contraception.

Exclusion Criteria:

1. Pregnant or lactating woman
2. Oral contraceptives during last three months, including hormonal IUD (trade name mirena).
3. Serious health problems.
4. Unexplained menstrual disorders.
5. Treated by hormones (estrogen and progesterone).
6. For healthy: Irregular or abnormal test results.