Galangal is a rhizome that is related to and resembles ginger, but has a mildly mustardlike, slightly medicinal taste; ginger is not an acceptable substitute. It is sold both whole fresh and as dried slices; halve the quantity when using dried. Galangal is also called Siamese ginger, kha in Thailand, and lengkuas or laos in Indonesia and Malaysia.   Nutritional Facts It is a good source of dietary fibre and vitamin B1. It has no cholesterol.   Medicinal / Therapeutic Use Asian medicine known to treat diarrhoea and vomiting.