Lignum vitae (Guaiacum officinale).Plant Part Used: Stem, wood.Dominican Medicinal Uses: Stem, wood: tincture, orally, for upper respiratory tract infections, skin ailments, arthritis and venereal disease; tincture, externally, for arthritis, rheumatism, joint pain (also orally in small amount); decoction, externally, to prevent hair loss.Safety: Considered safe is used appropriately; adverse effects include skin rash, diarrhea, gastroenteritis and intestinal colic.Laboratory & Preclinical Data: In an animal study of a closely related Guaiacum species, the following effects were shown: anti-inflammatory and hypoglycemic.* See entry for Guayacán in “Part 3: Dominican Medicinal Plant Profiles” of this book for more information, including references.