There is provided a nerve repairing agent, anti-ulcer agent or the like comprising an extract from a marine organism selected from organisms belonging to the class Holothuroidea, the phylum Porifera and the order Actiniaria or a material removed from a viscus of the organism. The extract has the following properties (1) to (4): (1) it is a almost colorless, transparent and viscous liquid having a slight fishy smell, or a almost white powder having a slight fishy smell which, when dissolved in water, is almost colorless and viscous; (2) a solution prepared by dissolving the liquid or powder in water shows the maximum absorbance at a wavelength of 264.+-.10 nm; (3) a solution prepared by dissolving the liquid or powder in water shows an acidic pH value; and (4) it has at least one effect selected from a cranial nerve repairing effect, a nerve-growing effect, an insulin-releasing effect, an immunopotentiating effect, a noxious pain preventive effect, a neurogenic pain preventive effect, a diabetic sensory neuropathy ameliorating effect and an ulcer preventive effect.