If you want to use aromatherapy for PMS relief, here's a list of essential oils that might help:
Source: The Complete Book of Essential Oils and Aromatherapy
The book explains the best essential oil(s) will depend on the nature of your symptoms and gives blends based on various PMS symptoms.
For general relaxation, diffuse the essential oil(s) of your choice. Or add an essential oil to a carrier oil for a massage.
Here's one general PMS blend:
Make the blend in a small dark bottle.
To use in the bath: Dilute 4 to 6 drops in one teaspoon milk or carrier oil. Stir into a warm bath.
To use for massage: Dilute 8 drops in four teaspoons carrier oil.
If you have cramps, see essential oils for menstrual cramps. Otherwise, here are more massage and bath blends for PMS relief.
Make a massage oil by blending the listed ingredients. Use the oil to either do self-massage, especially on your abdomen, lower back, and hips, or get a massage from a friend or professional massage therapist.
For tender breasts:
Make a massage oil for painful breasts by combing 60 drops geranium essential oil and 2 tablespoons carrier oil. Gently rub a little on and around your breasts a few times a day.
To make an aromatherapy bath blend, mix the recommended essential oils with 1 teaspoon carrier oil or milk and add the blend to a warm bath.
To relieve PMS depression or apathy:
To reduce fluid retention:
Other essential oils useful to help relieve water retention include grapefruit and carrot seed.
To improve your mood:
To relieve tension and volatility, diffuse this blend:
If you can't stop crying, place one drop of either clary sage, geranium, or rose on a tissue and inhale deeply.
Source: Essential Oils For Healing
I recommend Young Living essential oils.