Caprifoliaceae
Viburnum
opulus
Guelder Rose, Snowball Tree,
Astringent, Bitter, Antispasmodic, emmenagogue, nervine, sedative
the Bark
Bitter viburnin, valerianic acid, salicosides, resin, tannins. Hydrquinones: arbutin, methylarbutin, and free hydroquinone.Coumarins- scopoletin, esculetin. Trierpenes- oleanic and ursolic acid derivatives. Iridoid glycoside esters. Polyphenolics - astragalin, paeonoside, catechins.
In the Ayurvedic system it is said to reduce Vatta and Kapha and increase Pitta. It is a tonic to the uterus, stimulates menstruation and is useful for menstrual cramps and uterine spasms. Because of this it relieves dysmenorrhea. It can be used to tonify the uterus if there have been previous miscarriages. It can be used bleeding in menopause. Scopoletin is antispasmodic.
https://www.theherbalist.com.au/herb_gallery/cramp-bark