Heparin

Heparin is an anticoagulant (substance that stops blood clots) discovered by Jay McLean and William Henry Howell. It is generally injected under the skin or into veins. As of now it seems safe to use on pregnant people. It is identified as a glycosaminoglycan (long polysaccharide (the stuff that cells are made of) chains consisting of long repeating disaccharide chains.
The discoverers first extracted heparin from the guts of animals such as turkey, atlantic salmon, mice, and even humans. The specimen of choice is a fresh, nonhemolyzed (intact red blood cells is broken) plasma anticoagulated by fluorides. Overdose can cause heparin-caused thrombocytopenia, a condition where white blood cells attack platelets (the stuff in your blood that heal wounds), causing a slowed heal time, bad breakdown of tissue in the leg, heart infections, and strokes, none of which will be benign.
Heparin is rated one of the World Health Organization's List of Essential Medicines, showing its value and popularity and rate of success.