castile bar soap by kirk’s | natural soap for men, women & children | premium coconut oil | sensitive skin formula, vegan | fragrance-free/unscented | 4 oz. bars - 4 pack kirk's since 1839, kirk's original coco castile soap has given the consumer a high quality, all natural soap at an affordable price. current national market research ranks kirk's original coco castile soap as the top selling all-natural bar soap. 'castile' originally referred to the highly-prized vegetable based soap produced in castile, spain. for centuries this soap was considered 'the soap of royalty' because of its luxurious lather and gentleness to the skin. today, 'castile' refers to any vegetable based soap.