Heparin
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.