When it comes to stopping bleeding, your body is like a tiny, highly trained emergency
team—sending platelets, clotting factors, and a flood of chemical signals to patch up the
damage before you even notice it. But sometimes even the best emergency team needs a
little backup to get the job done!
WHAT IS HEMOSTASIS?
Hemostasis is the body’s biological process for stopping bleeding after an injury to a blood
vessel. It is the first step in wound healing and consists of three main mechanisms:
👉🏻Vasoconstriction — blood vessels constrict to reduce blood flow.
👉🏻Platelet plug formation — platelets stick together to form an initial seal.
👉🏻Coagulation — a cascade of chemical reactions turns blood into a gel (fibrin clot) to
firmly stop bleeding.
Hemostasis is a highly efficient natural process. However, in many real-world situations (such
as first aid emergencies or specific medical conditions), additional help is required to
effectively stop the bleeding. Such help sometimes comes …. from the oceans!
SEAWEED TO THE RESCUE: STOPPING BLEEDS NATURALLY
Seaweed has a long history of use in traditional wound care, particularly among coastal
communities who relied on readily available marine resources. Fishermen and sailors used
to apply fresh or dried seaweed directly to cuts and wounds to help absorb blood,
protect the injury, and promote healing.
Brown seaweed was especially valued because of their soft texture when wet and their ability
to hold moisture, which helped cover wounds and limit continued bleeding.
Over time, scientists discovered that compounds within these seaweeds—especially alginates—were responsible
for many of the beneficial effects observed in traditional use, allowing ancient knowledge to
be transformed into modern, evidence-based wound care materials.
FROM TRADITIONAL USE TO SCIENTIFIC EVIDENCE AND INDUSTRIAL
APPLICATIONS
Alginate (also called alginic acid) was first discovered in the nineteenth century by the British
chemist E. C. C. Stanford, who extracted this natural substance from a brown seaweed
variety called Laminaria. Early publications and studies focused on its physical and chemical
properties, such as its ability to absorb fluids, form viscous solutions, and create gels.
While alginate was initially exploited in industries such as food, textiles, and paper, its
biocompatibility and gel-forming properties led the pharmaceutical industry to adopt it in the
mid-20ᵗʰ century as a versatile excipient used to support and control drug delivery.
Seaweeds — especially brown seaweeds — are large marine algae
rich in natural polysaccharides such as alginate. These polymers have
unique physical and chemical properties that make them useful in
wound care.
Alginate is extracted from the cell walls of brown seaweed such as
Laminaria species. It contains molecular blocks of mannuronic and
guluronic acid that can form gels when in contact with fluids.
Around the same time, specific interest in the hemostatic potential of alginate emerged
through the work of British surgeon George Blaine, who, during the 1940s, investigated
calcium alginate use on wounds. Blaine observed that when applied to bleeding wounds,
calcium alginate not only absorbed blood but also promoted clot formation by releasing
calcium ions—an essential factor in the coagulation process.
In France, surgeon Jean Gosset was among the first clinicians to draw attention to the
hemostatic potential of alginate materials. At a 1949 session of the Académie de Chirurgie
(Academy of Surgery) in Paris, Gosset shared clinical observations using calcium alginate on
various wounds and concluded that it offers genuine potential. He encouraged its preparation
on a commercial scale and supported the launch of Coalgan® in 1949
www.coalgan-gamme.com
The works of Blaine and Gosset marked the first serious clinical explorations of alginate as a
medical material, transforming a natural seaweed extract into a scientifically recognized
hemostatic agent. This paved the way for the development of calcium alginate medical
devices used in advanced wound care for hemostasis and tissue repair (www.brothier.com).
HOW STOP HEMO® STOPS BLEEDING: MECHANISM OF ACTION
Inspired by the natural properties of algae, Stop Hémo® changes upon contact with blood.
This physical and chemical transformation allows it to act both mechanically and biologically,
promoting effective coagulation. Its calcium alginate:
1- Absorbs blood
2- Hydrates and forms a protective gel, which acts like a temporary barrier, trapping
blood cells and clotting factors at the wound site
3- Releases calcium ions at bleeding site (calcium ions are factor IV of the coagulation
cascade, essential for the clotting process)
4- Does not stick to the newly formed clot: the gelified structure ensures an atraumatic
removal.
This nature-inspired action makes it a suitable first-aid solution for everyday situations.
Ready to use and designed for life’s unexpected moments, it offers calm and confidence
Coalgan®, a hemostatic swab indicated for the treatment of minor
nosebleeds, is made of calcium alginate fibers and thus delivers the
hemostatic properties of algae. It is nowadays internationally available
under the brand names Stop Hémo®, BleedCease®, NasalCease® and
Chicare® (www.brothier.com)
KEY POINTS TO BEAR IN MIND
The story of seaweed in medicine is one of transformation: from traditional use along coastlines
to sophisticated biomedical treatments in modern households and hospitals.
Seaweed’s physical and chemical properties are particularly useful in hemostasis: it absorbs
blood, hydrates, forms a protective gel and releases its calcium ions at the bleeding site to
support the natural process of coagulation. Those properties, once observed by sailors, have
since been harnessed and refined through industrial processing—transforming alginate into
hemostatic and healing medical devices.
Thus, the ocean gave us a powerful resource, and we used it wisely – advancing patient care
while reinforcing our responsibility to protect marine ecosystems.
Join the movement by exploring the work of our partner, 1Ocean, and be part of a more sustainable future for
healthcare, the ocean and the climate: https://www.mission-1ocean.com/projet/forets-sous-
marines-un-enjeu-pour-lhumanite/ Restoring our underwater forests is more than protecting biodiversity,
it’s a bold step toward safeguarding our climate for the future.
— Alexis Rosenfeld, Project Leader at 1 OCEAN
when bleeding occurs – whether from a sudden nosebleed, delicate gum bleeding, or a minor
skin injury – helping you care for yourself and your loved ones when it matters most.
SUSTAINABILITY AND THE FUTURE OF SEAWEED IN MEDICINE
As sustainability becomes a central concern in healthcare, seaweed stands out as a natural
resource uniquely suited to meet both medical and environmental challenges. Unlike
terrestrial crops, seaweed doesn’t require fertilizer, pesticides, freshwater, or land, and it
grows rapidly.
This ease of cultivation and exceptional sustainability are matched by a rich biochemical
diversity, positioning seaweed as both an environmentally responsible resource and a
promising source of therapeutic compounds.
Seaweeds are rich in polysaccharides, polyphenols, proteins, and pigments, which possess
various therapeutic properties. These compounds have shown potential as anti-inflammatory,
antimicrobial, antiviral, antitumor, and antioxidant agents, among others.
Stay tuned for our publication regarding seaweed benefits in healing by reducing
inflammation, fighting bacteria, and promoting tissue growth!
Sources:
1. Hemostasis, https://my.clevelandclinic.org/health/symptoms/21999-hemostasis, accessed
on 06/01/2026.
2. Pérez-Lloréns, J.L., Critchley, A.T., Cornish, M.L. et al. Saved by seaweeds (II):
Traditional knowledge, home remedies, medicine, surgery, and pharmacopoeia. J Appl
Phycol 35, 2049–2068 (2023). https://doi.org/10.1007/s10811-023-02965-6.
3. Hylenne Bojorges, Amparo López-Rubio , Antonio Martínez-Abad , María José Fabra ,
Overview of alginate extraction processes: Impact on alginate molecular structure and
techno-functional properties, Trends in Food Science & Technology, Volume
140, October 2023. https://doi.org/10.1016/j.tifs.2023.104142
4. Blaine G. Experimental Observations on Absorbable Alginate Products in Surgery : Gel,
Film, Gauze and Foam. Ann Surg. 1947 Jan;125(1):102-14. doi: 10.1097/00000658-
194701000-00011. PMID: 17858907; PMCID: PMC1803201.
5. Histoire de l’hémostase locale, Académie de Chirurgie Magazine, 3 ème trimestre 2012.
6. Pereira L, Cotas J. Seaweed: a sustainable solution for greening drug manufacturing in
the pursuit of sustainable healthcare. Explor Drug Sci.
2024;2:50–84. https://doi.org/10.37349/eds.2024.00036
NET26SHE03A – janv 2026
