## 1 Introduction  
Yarrow is a perennial of the family Asteraceae that grows to a height of 80 cm. It is native to regions with a temperate climate in the northern hemisphere (Europe, Asia, and North America). It blooms from June to October [1,2]. Its umbrella-shaped inflorescence consists of white, yellow, orange, pink, red, or purple flowers, depending on the variety. The \"Paprika\" cultivar has bright red flowers with yellow centres, which change colour during their development (Figure 1).  
Yarrow contains essential oil (containing compounds such as camphene, \(\alpha\)- and \(\beta\)-pinene, limonene, camphor, and linalool), flavonoids (e.g., caffe acid, quercetin, apigenin, rutin, lutein, morin, myricetin, naringin, naringin, achillin A, and millifolide A, B, and C), coumarin, sesquiterpene lactones, polyacetylenes, triterpenes, tannins, sterols, and organic acids [1, 2, 3]. Therapeutic effects are attributed to both the herb (_Millefoli herba_) and its flower (_Millefoli fios_), and the raw plant parts exhibit multi-faceted biological activity. Various parts of the plant have been used in traditional medicine as material with diaphoretic, astringent, tonic, stimulating, hepatoprotective, antimicrobial, and anti-inflammatory effects [1,3,4]. It has been recommended for conditions such as cough, flu, kidney stones, hypertension, menstrual disorders, rheumatoid arthritis, gout, degenerative joint disease, cystitis, diabetes, and indigestion [3, 4, 5]. Decoctions have been used to treat haemorrhoids and headaches. This application is associated with the content of alkaloids in yarrow leaves, as they exhibit anti-inflammatory and analgesic activity [1]. Antioxidant and anti-aggregation effects are ascribed to the flavonoid glycosides contained in yarrow [2]. A standardized aqueous herb extract exerts antispasmodic effects and can be used to treat stomach problems [6]. Externally, it can be used as a sitz bath for gynaecological disorders [1]. Yarrow is also an interesting material for external skin care and medicinal applications. According to the Cosmetic Ingredient Review Expert Panel, _A. millefolium_ flower extract and flower/leaf/stem extract are safe for use in hypoallergenic cosme [7]. According to the current database of cosmetic ingredients (CosIng) [8], _A. millefolium_ is one of the two species of the genus _Achillea_ used as an active ingredient in cosmetic formulations, along with _A. asiatica_. Yarrow is used as a skin-rejuvenating, anti-seborrheic, cleansing, refreshing, soothing, and tonic agent, as well as a skin conditioner, humectant, and fragrance ingredient [3,7]. The European Medicines Agency (EMA) monograph on _Millefoli herba_ describes therapeutic indications for its topical use in small superficial epidermal excoriation, as well as in the symptomatic treatment of minor skin inflammations, such as sunburn and mucosal lesions, and in the healing of minor wounds [9]. In addition,  
Figure 1: _Achillea millefolium_ L. var. _paprika_ (photo [PERSON]).  
literature reports indicate that _A. millefolium_ is recommended for slow-healing wounds and for dermatological conditions such as eczema, psoriasis, and boils [4; 5; 8].  
The aim of the present study was to analyse the chemical composition and the protective, antioxidant, and antimicrobial properties of extracts of yarrow herb of the \"paprika\" cultivar, which has not previously been studied in this regard. In addition, the sun protection factor of a model formulation based on the extract, as well as the rheological characterisation of the formulation, which determines its potential applications, was conducted.