Benefits of Yarrow - It is an excellent herb for children. It is helpful in relieving fevers, shortening the duration of cold and flu, helping improve relaxation during illness, and relieving cramps associated with hormones or illness. Applied topically, it is helpful with skin itching, rash or other issues.  An external tincture or poultice will often help with hemorrhoids, rashes and broken skin. Some people will notice relief from allergy symptoms by drinking a tea of yarrow and mint.
Yarrow is a mild, slow, and stimulating diaphoretic that is best used for the first stage of acute fevers, and for atonic and relaxed tissues where there is free discharge or passive haemorrhage of bright red blood. 
Yarrow tincture is recommended to stimulate the appetite and tone the digestive organs, and given for the following specific indications: Acute stage of colds; influenza and respiratory catarrhs; chronic diarrhoea and dysentery; epistaxis; intestinal haemorrhage, bleeding haemorrhoids, uterine haemorrhage; profuse or protracted menstruation; and leukorrhea.” 
The herbal tincture is taken internally to treat colds, fevers, and indigestion, and used topically in skin treatments of slow-healing wounds. 
How to use Yarrow: 
Add a dropper full to wheat bags to induce restful sleep
In a tincture for times when falling asleep is difficult
In teas with mint and chamomile during illness
As a tea, tincture or poultice on skin for rashes and itching
As a tincture to help ease menstrual cramps and hormone issues (not for use during pregnancy)
Yarrow tea often helps with congestion symptoms from allergies and illness
Adding yarrow tincture to skin lotions, oils or salves can help with eczema or dry skin
Add a strong yarrow tea to a child’s bath for a high fever that you want to bring down naturally
Since it is helpful in stopping bleeding and avoiding infection, poultices of yarrow can be helpful on wounds
 
Tinctures are made with fresh herbs extracted in alcohol.  Diluting for children or pets is suggested.  Add to boiled water and let sit for 10 minutes and alcohol traces will dissipate.