I found this info online re Blood stasis. This info is kind of long, and I totally recommend you read all this info below, but Ive highlighted the specific castor oil info for you.
Blood stasis syndrome, or blood stagnation is an important underlying pathology of many disease processes according to traditional Chinese medicine.
Since the blood has so many important jobs to do to keep us alive and well, the quality of blood flow in the body is one of the most important aspects of health. There is a term unique to Chinese Medicine, Blood Stasis, which describes a situation where the blood isnt moving as well as it should be, and is often stuck.
The following I copied from a book I just finished reading called The Infertility Cure: The Ancient Chinese Wellness Program for Getting Pregnant and Having Healthy Babies" By Randine Lewis.
When a woman comes to my clinic with stagnant uterine blood (which produces fibroids, endemetriosis, or just dark, clotty, brown, or sticky menstrual blood) one of my first goals is to cleanse the uterus using several invigorating herbs. After a while her menstrual flow should be a fresh red color.
Uterine fibroids are usually due to blood stasis. Blood stasis also produces sharp stabbing ovary pain during the ovulation period.
For conception to occur, all the energies in the body must be free-flowing and moving, like waters in the river bringing life through the land where it passes. Fibroids and endometrial growths are like rocks in that river, preventing the embryo from mooring safely within the walls of your womb.By eliminating blood stasis, balancing the bodys other energies, and and softening the concretions within your reproductive organs, you can restore the flow of the river of life through you and provide a clean, clear harbor for your unborn child.
She recommends the following:
Perform deep breathing exercises and meditative practices
Regular moderate daily exercise helps improve circulation. Yoga is also helpful, but do not perform inversion techniques during menstruation. The energetic flow must always be descending.
Wear loose comfortable clothing
Take warm baths (with aromatherapy if you wish)
Use essential oils like frankincense, myrrh, clary sage, peppermint, lavender, rosemary, juniper and thyme
Use heating pad or hot water bottle on your abdomen during and after menstruation
Apply warm castor-oil packs on your abdomen to invigorate your blood, assist the lymphatic system, and balance hormone levels. Apply warm castor oil to the lower abdomen and cover with plastic wrap 2-3x a day during the premenstrual and menstrual period (if you are actively ttc, use only during the menstrual period).
Hope this helps!
