In this report, we reviewed recent literature on physiologically active substances from sea cucumbers (SCs) and their activities together with results obtained from our study. Preventive properties against lipid metabolism were reported in rats using a whole SC preparation with no particular constituent specified. Administration of the preparation lowered serum and hepatic cholesterol levels and improved the HDL/LDL ratio. These functions may be attributed to the stimulatory effect of the extract on the secretion of cholesterol in feces. Novel fucosylated chondroitin sulfates (FCSs) from Ludwigothurea grisea significantly induced fibroblast growth factor 2-dependent angiogenesis in human umbilical vein endothelial cells (HUVECs). The proangiogenetic activity seemed attributable to the action of the sulfated fucose branches on the polysaccharide.SCs contain mycosporine-like amino acids (MAAs) that are capable of absorbing UV. A biogenetic precursor of MAAs was first reported in SCs. The anti-proliferative effects of a branched chain fatty acid from a sea cucumber on prostate cancer cells was reported with the activity of 5-lipoxygenase. Glycosphingolipid constituents in SCs have been systematically analyzed over the past ten years. The results showed that the gangliosides in several SCs differed from those of mammals in that a sialic acid of SC gangliosides directly binded to glucose of cerebroside. Neuritogenic activity of the glycosphingolipids was demonstrated in vitro experiments and may lead to the development of therapeutic products for neurological disorders. Our study also showed that sphingoid bases, the hydrolyzed products of glycosphingolipids from SCs, induced significant apoptosis in several tumor cell lines.