The cellulose used in the manufacture of medical grade paper is usually obtained from the wood of trees originating in Nordic countries. This is because in these countries there is a constant presence of snow and cold temperatures that make the growth of the tree slower and more progressive, forming a characteristic type of fiber especially resistant. Low temperatures also prevent the proliferation of pests, eliminate the need for fumigation and the use of chemicals, also resulting in greater purity of the material. This cellulose does not receive any type of chemical treatment, with it the fibers are manufactured with exactly the same degree of purity as when extracted from trees. Once the production process of the cellulose fibers begins, different measures are taken to produce more long fibers than short ones, since the long fibers are those that make up more than half of the medical grade paper structure. When manufacturing medical grade paper with pure cellulose no optical brighteners are used.