Introduction. There is a wide range of seawater products for nasal lavages. Their efficacy and superiority over conventional saline solutions are not well established. Objectives. To analyse the best-selling seawater products, as well as reviewing the most recent literature regarding nasal lavages. Methods. Comparative study of composition, administration mode, age indicated for its use, price and bibliography provided on the web of the seawater products usually available in pharmacies. Analysis of the bibliography provided and review of the scientific evidence regarding nasal lavages with saline solutions or seawater. Results. 44 products from 11 manufacturers were analysed. The concentration of sodium chloride varies from 0.9% to 2.5%. The most frequent mode of application is spray. The addition of plants, salts and other components is common. Only two brands provide bibliographic refe...