Chitosan dressing are most promising due to effective blood stop and possible additional properties like antibacterial and stimulatory to regeneration. It is not extensively present in the environment. However, it can be easily derived by the partial deacetylation of a natural polymer chitin. To be named “chitosan”, the deacetylated chitin should contain at least 60 % of D-glucosamine residue. 

How It Works: 

Chitosan is a positively charged polysaccharide that attracts blood cells which are negatively charged. This attraction causes an extreme adherence when in contact with blood. The red blood cells form a very tight coherent seal over the wound as they are drawn into the dressing 

Applications: 

If you suffer from hemophilia you can use them to stop bleeding quickly. These dressings can be useful in many situations such as: hiking, biking, construction worksite, over seas missionary work, or any other dangerous activity. 

(http://www.instructables.com/id/Make-Your-Own-Chitosan-Bandages/)