- Centaurium (centaury): uses. Earache: garlic oil, onion juice. Fennel: uses. Heartburn: antacids. Hyssop: uses. Insomnia. Lighten eye color. Pennyroyal: the herb vs. the EO; the menstrual cycle; wild yam. Shingles. St. John's wort: photosensitivity. Yarrow uses. Book Navigation ‹ Uterine fibroids: Vitex, raspberry. up Centaurium (centaury): uses. ›