Yarrow isn’t as well-known as other medicinal herbs such as echinacea or peppermint, but it’s nonetheless a useful tool for a more natural approach to health and wellness. Yarrow’s  uses range from aiding in clearing blood clots to menstrual issues. It can also be used cosmetically!
WHAT IS YARROW?
Yarrow, or Achillea millefolium, is also commonly known as milfoil. It is a leading backyard herbal medicinal plant. This beneficial herb often goes unnoticed as an unsightly lawn weed, however, according to legend, the infamous Achilles used yarrow as a field dressing  for his soldiers’ wounds during the Trojan War. The plant is named after him. The parts of the plant above ground are commonly used in herbal medicines.
Yarrow is mostly native to the temperate regions of the world (the Northern Hemisphere) and is commonly found in North America, Asia, and Europe. Yarrow has beautiful little white disk flowers. It has a strong, sweet scent that makes it a great essential oil.
Shampoo: Yarrow might have properties to help naturally boost hair growth, but the herb is especially useful for treating oily hair and an oily scalp condition. You could try using some yarrow essential oils. 
Try adding 4 to 5 drops of the essential oil to your regular herbal shampoo before applying it to your scalp in the shower. It will refresh your hair and scalp, while also encouraging new growth at the same time.
Yarrow is an antiseptic meaning it protects wounds from infection after being exposed to foreign bacteria, fungi, or viruses. It also aids the body in reduction of topical skin fungal problems, skin rashes, cystic acne, and pimples. If you have any scars from pimples, boils, or acne, yarrow will help cure them. You can try mixing a small amount of alcohol-free yarrow extract  with other natural moisturizers for the best results. As an anti-inflammatory, yarrow will help calm redness or swelling in the skin caused by acne, rosacea, or even eczema.
Yarrow has numerous medicinal properties  due to its high concentrations of terpenes. These compounds evolved as defense mechanisms to deter herbivores and attractant predatory insects that feed on herbivores.
They are also what provides the natural chemical compounds that can heal and protect the human body while providing a stimulating burst of bitter flavors and often pleasant aromas.
Wound Healing/Stopping Bleeding: as an anti-inflammatory and antiseptic herb, yarrow will help wounds heal faster without infection. It is a helpful remedy to stop the bleeding of minor wounds, such as scrapes or bug bites. Use a pinch of the dried yarrow herb and apply it directly to the wound.
Aids In Digestion and Detoxification: According to Dr. Mercola‘s website , yarrow’s bitter components and fatty acids encourage proper bile secretion from the gallbladder, which can then improve digestion and keep gallstones from forming. The Cherokee, Gosiute, Iroquois, and Mohegan nations have traditionally used yarrow for digestive support. Bitter and aromatic herbs help digestion by stimulating the production of bile and pancreatic juices. Try making a yarrow tea from dried herbs to help soothe an upset stomach and aid the body in natural detoxification.
Helps Relieve Cramping and Menstrual Pain: Yarrow can also help regulate menstrual periods, particularly controlling heavy flow. It is antispasmodic and anti-inflammatory which means the herb helps the muscles of the uterus to work more efficiently without spasms and cramping up. Because uterine cramping and inflammation are the cause of the pain associated with menstrual cramps, yarrow helps by relieving inflammation and congestion of the uterus. This can aid in pain reduction, as well as proper circulation to the reproductive organs. When using Yarrow to relieve menstrual cramps, it is best to prepare in advance of the pain,  writes Natural Fertility Info.  A low dose in the form of a tea, or liquid extract every day leading up to menstruation may be best. The dosage may be increased during menstruation if needed to soothe the pain and discomfort.
Yarrow has numerous uses and can be a beneficial addition to any herbalist or naturalists home but it can be risky to cats. Yarrow can poison a cat,  so it is best to keep your furry feline friend from eating copious amounts of this herb. Because the herb is so bitter, it is unlikely your cat will eat enough of the plant to poison itself, however, it is important to take note of this possibility.
*This article is for informational purposes only. It is not meant to treat, cure, or diagnose any health conditions or illnesses. If you have questions about beginning an herbal supplement or a health concern, please contact a medical professional.