The invention relates to saturating various fluid media with oxygen, for example for aeration and can be used for the food industry, pharmaceutics, perfumery and cosmetics, physio- and aromatherapy, water supply systems, fishing and agriculture, including producing beverages, food additives, drugs, novel perfume and cosmetic products, inhalation and bathing, for improving the habitat and increasing a productivity of fish and other beneficial animals and microorganisms in aquariums, ponds, pools and for producing means for treating plants and animals. The method of liquid medium treatment includes passage of oxygenated gaseous medium flow through it with the gaseous medium previously saturated with phyto-egestas of vegetating or cut plants. The technical result is saturation of liquid media with health improving, salubrious, improving ecological stability and fertility of animals, useful insects, protozoal micro-organisms and plants, reducing all-up the number of deleterious bacteria and viruses ingredients continuously renewable in a natural way, for example, air ions, aromatic oils, phytoncids.