Biofoam
From Halopedia, the Halo wiki
Summary
Self sealing Biofoam was a marvel of UNSC medical accomplishment in the 2500's. Biofoam is a healing, coagulant foam that is inserted into the skin and even deeper into the body itself. This foam keeps damaged organs in place and helps stop bleeding and hemorrhaging. It is, unfortunately, very painful to use. It is an improvised medical option when there are no medics available. Normally bottles of biofoam are found in a Health Pack.
