Marine organisms, mostly invertebrates, have captured the attention of the scientific community because of interesting chemical compounds with specific biosynthetic pathways and physiological roles. Molluscs, sponges, bryophytes, and similar organisms produce chemically very potent compounds that enter the medical pipeline as additives to existing or new drugs. Sponges are responsible for 30 % of all natural products obtained from the marine environment. Pharmaceutical interest in sponges began about 70 years ago. The bath sponge, Spongia officinalis, is a Mediterranean sponge that has captured attention since antiquity and was valued in commercial circles. Its primary commercial use was for bathing, and like other Mediterranean sponges of this genus, it was also used for various medicinal purposes, for drinking and paint application. Recently, research has shifted focus to isolated secondary metabolites, synthesized directly in sponge cells or indirectly by its commensal microbial communities. Products obtained by isolation from various sponges show antiviral, antitumor, antibacterial, antifungal, immunosuppressive, antiinflammatory, neurological, bioregenerative, antidiabetic, and antimalarial effects. Two such products, nowadays recognized therapeutics, are Cytarabine and Vidarabine isolated from the Caribbean sponge, Tethya crypta. Compounds obtained from bath sponge show mostly antitumor and cytotoxic effects, though antibacterial and neurological activities have been frequently reported in the literature. Cultivation of common sponges began at the end of the 18th century and today stands as an alternative to collection from nature, which stresses already damaged populations. Although they are less represented in the scientific literature, Mediterranean sponges show great potential for the development of new biomaterials with applications in biomedicine and other industries.